How a heat pump works

https://hvac-learning.com/courses/heat-pumps-part-1/

by WatchdogReset • 3 years ago

246 324 3 years ago

The heat pumps are one of the means of heating (and air conditioning) in the heart of the news. What is their principle of operation. You can ask questions here if there are points to clarify in the course

jcstauffer• 3 years ago

I'd like to get a heat pump to replace my existing baseboard hot-water system (currently powered by an oil furnace) without converting to a heated air system.

From what I've read, that's not quite feasible yet, since current systems can't produce a high enough temperature.

What are the prospects of that technology becoming viable in the next few years?

zacharybk• 3 years ago

It partially depends on your climate. I’m in Portland, Maine, so for us, we have a natural gas furnace with radiators, but they’re heavily supplemented by a few heat pumps. For us, the temperature frequently gets very low in the winter, sub 10°F, and this is the point when heat pumps aren’t as efficient. An ideal set up in a small home could be heat pumps running off solar and a woodstove for when it gets really really cold.

suoduandao22• 3 years ago

Solar hot water would probably be a better fit for your situation.

sokoloff• 3 years ago

Figure out the minimum flow (supply) temperature that can meet your building heat loss on the design day. If you have enough radiation, you might be able to get by with 135°F flow.

I have baseboard in the attic and cast iron rads on the main level. I have the flow set to 126°F until the outside air temp drops below 30°F and then I increase by 2°F for every 4°F change in OAT. So at 2°F OAT, I have 140°F flow.

That’s enough to maintain temp in my fairly poorly insulated 1920s house near Boston. It’s enough to slowly recover temp as well.

140°F is a stretch for air to water heat pumps, but you could reasonably use an A2W for most of the year and supplement with a 9kW (31KBTU/hr) electric boiler as emergency supplemental heat and use that a couple days per year.

What killed it for me (and the reason I have a fairly new gas boiler installed) is the upfront cost was utterly uncompetitive.

If you have a condensing boiler, set the high-limit or flow temp to 130-135°F and see how your house handles it on the cold days. You can measure and calculate all you want, but nothing beats trying it.

LazyMans5• 3 years ago

This guy is a great resource if you want to understand what goes into a proper A2W system install. In Europe, it seems by law they are required to do heat loss calculations to size an install. In the US, it seems to be a little more loose. https://www.youtube.com/watch?v=0IvGe4JZLSU

sbradford269• 3 years ago

So CO2 heatpumps are starting to become available in the US which can run higher temperatures. But most likely the best option would be to switch to radiators that don't require as high of temperature to operate. Something like underfloor heating or panel radiators.

The other option that is common in New England is to keep the baseboard oil heat and get mini splits. Then run the mini splits for heat and if they cannot keep up switch to the oil heat.

hcknwscommenter2• 3 years ago

What works for me in the northeast with an old house is a high velocity small duct air handler/distribution system (unico) coupled with a Bosch cold climate heat pump, with an oil furnace backup. This is forced air, so not exactly what you are looking for and I get that the heat from those baseboards is a better quality/less drying form of heat. I could upgrade to add a whole house humidifier to address this a bit. I use the heat pump most of the year, down to an outside temp of about 25F, although Bosch says I should be good down to 5F. The oil furnace runs basically Jan/Feb (but not as much this Feb as it's like 50F today). I've also extensively sealed/insulated the house (although there's always more of that to be done in an old house). It's a pretty good solution. I'd love for the air to water heat pump tech to work better, but I got tired of waiting.

masklinn2• 3 years ago

From what I've read, that's not quite feasible yet, since current systems can't produce a high enough temperature.

Is it because baseboard hot-water systems have limited exchange surface surface and thus need very high temperatures to do anything?

WatchdogReset10• 3 years ago

I think this is possible. I will ask to a teacher of hvac-learning and come back to you asap. But basically you can heat water instead of air with a heat pump.

WatchdogReset10• 3 years ago

As others comments said, it depends on the climate : The problem is that the power/performance of the heat pumps decreases with the cold weather and the necessary increase in the temperature of the heating water, which obliges to keep the boiler for the cold weather. This is a problem for the heat pumps without probable solution and little progress to wait. The solution is to insulate the house very well so that its needs can be covered by the heat pump with less hot water. Divide the losses by 2 at least.

mastermedo• 3 years ago

I'm getting an error when trying to load the page: > Error establishing a database connection

https://web.archive.org/web/20230210134443/https://hvac-lear...

The archive.org is pretty slow on this one as well, as it is an interactive site.

Neil44• 3 years ago

OOM Killer strikes again - it always loves mysqld for some reason...

WatchdogReset10• 3 years ago

If you have advice for me, I'll take it ;) can exchange with HVAC courses

WatchdogReset10• 3 years ago

The website is new and not fit yet for such numbers of visit, so sometimes it does not render well pages. I(admin) still in the process of understanding how to build a nice website. I will analyze what happened and enhance it. I'm sorry for the inconvenience !

yreg• 3 years ago

Technology Connections has a good video on heat pumps. (Actually several of them, I link the newest one.)

https://www.youtube.com/watch?v=MFEHFsO-XSI

generaltsos2• 3 years ago

That channel is fascinating. They have created some incredibly interesting projects.

manigandham• 3 years ago

What have they created? You might be thinking of Tech Ingredients - https://www.youtube.com/@TechIngredients

pkulak3• 3 years ago

I just found this guy too. He answered a lot of questions I had about efficiency and use below freezing.

https://youtu.be/fxEqVuiHhM0

kenmacd3• 3 years ago

I like his videos, but I don't trust his numbers in this one. He shows a COP of ~1 when it's 10 degrees out. These are the easiest possible conditions for the HP, and where all the specs show the highest COP. His graph showing the HP is running equal to a baseboard heater seems very suspect.

ASalazarMX2• 3 years ago

Can't recommend this channel enough, it's like the Captain Disillusion of home appliances. The video about hurricane lamps was the first I saw, and it solved questions I didn't know I had about their weird shapes.

barbazoo• 3 years ago

Their main channel is http://youtube.com/user/matthiaswandel

Casteil3• 3 years ago

He does, but he omits a lot of important considerations that make heat pumps impractical for normal Americans.

If he touches on them, it's briefly - if at all, e.g.:

- More expensive units, and more expensive to run power wise. It's always difficult to get adoption of new technology that's "better" but more expensive to buy & repair - to the point where RoI may never happen.

- Power grid implications during very low/record low temps e.g. shortages/blackouts, likely worse than those in summer if heat pump uptake is widespread.

- With a heat pump, you -need- an alternative source of heat - since some days when it's particularly cold, they just won't work, or work very inefficiently. Plus, if the power goes out... you're definitely not powering a whole house heat pump with a small generator like you could a natural gas furnace.

Edit: FWIW, I'd researched this topic heavily & seriously considered getting a heat pump to pair with a solar power setup. For a number of reasons (chief among them: no return on investment before the end of the heat pump's expected service life), I will not be getting a heat pump any time soon. That may change if prices drop dramatically, but that seems unlikely given their increased mechanical/electrical complexity.

nly• 3 years ago

- Better than resistive electric heating for the grid. Gas is going away so this is a problem that has to be solved anyway.

- Economies or scale will solve the repair and maintenance burden... hell, it's not like a gas boiler is maintenance free...fucking things requiring serving every year and break down all the time in the UK.

- almost noone has a generator when the power goes out anyway. This is a very wealthy American perspective.

guidoism3• 3 years ago

The alternative heat point is interesting, you don't need to be able to heat your entire house with alternative heat for extended periods of time. If properly designed, 99% of the hours of the year should be warm enough for the heat pump to provide 100% to heat and the remaining hours can be made up with a small space heater or a fire or something else minimal.

rainsford• 3 years ago

He does, but he omits a lot of important considerations that make heat pumps impractical for normal Americans.

Some form of this comment always comes up in these heat pump threads, and I never understand the idea that heat pumps are some elite affectation that doesn't make sense for anyone else. Many millions of Americans live in parts of country where it gets warm enough in the summer to justify central air conditioning and chilly enough in the winter that you need heat but the heating source doesn't need to handle super low temps on a regular basis.

A heat pump is literally one of the simplest ways to address the year round climate control needs for those people since it's a single system that handles both heating and cooling with only marginally more complexity than the air conditioner you'd want anyways. Throw in electric backup heat, which is probably the simplest backup and keeps the system all-electric, and you have a system able to handle a pretty broad range of temperatures all year. As heat pump technology gets better, the applicable temperature range gets colder and colder and makes heat pumps practical for a wider range of "normal Americans".

This isn't just theoretical. Heat pumps account for 17% of heating systems in the US, which isn't huge, but over 40% in North Carolina, South Carolina, and Alabama and a significant percentage in many other states as well. Obviously there are cases where heat pumps are at least currently impractical given the construction, climate, etc, but dismissing them as some effete toy seems a bit silly.

Edit: Interestingly, most states seem to have a significantly higher percentage of homes with electricity as their primary heating fuel than they do homes with heat pumps, suggesting a lot of homes with things like electric baseboard heating. While not all of those homes necessarily have central AC, using Georgia as an example, 85% of homes have central AC and 53% use electricity as their main heating fuel, while only 29% have heat pumps. That suggests quite a few homes with central AC that use electric baseboard or similar. Heat pumps for those homes seem like they'd be very practical.

snozolli3• 3 years ago

With a heat pump, you -need- an alternative source of heat - since some days when it's particularly cold

Modern heat pumps redirect some heat to prevent the coils from freezing. What you wrote is common FUD pushed by the oil & gas companies.

That said, you'd be a fool to live in an area with life-threateningly low temperatures and not have a backup heat source.

ryantgtg• 3 years ago

Just to soften a few of your confident declarations.

normal Americans

Please revise this phrase. America consists of many different climates and it's very unclear what you mean or why you chose the word "normal."

More expensive to run power wise

You're comparing new gas HVAC vs new heat pump. However, don't forget about all the folks that are purchasing a heat pump to replace an existing gas unit! For example, my gas unit (Goodman unit used in California) is old and not even energy star compliant! A new heat pump will be more efficient.

With a heat pump, you -need- an alternative source of heat

By 'you' are you referring to me (or, say, the ~7% of the US population that lives in my small area of the country)? If so, that's not true! It doesn't get too cold here. And I reckon there are quite a few areas in this country where it doesn't get cold enough for a heat pump to eat shit.

When you refer to prices and returns on investment, are you using a unit + professional installation cost (like $18k+ or something)? Or the unit itself (~$4.5k) plus perhaps a DIY installation costs (~$1.5-2k)? There is a big range there in costs, and the ROI is dependent on that.

irrational• 3 years ago

With a heat pump, you -need- an alternative source of heat

It's only a -need- in certain locations. The one I have claims to be fine down to -5 degrees. There is zero chance we will get anywhere close to that in my lifetime. Heck, even getting down to 32 is incredibly rare. So we are fine without an alternative source of heat.

As for other points, we have never had a power loss/blackout in the nearly 3 decades we have lived here. And electric is cheaper than gas due to nearby hydroelectric dams.

boringg4• 3 years ago

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push.

I understand that its for climate benefits but it feels very coordinated.

edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HVAC installers / heat pump manufacturers and governments are all pushing this hard right now. I believe in the benefit for most people and the climate benefits are great. I am always concerned on when there is large consensus on a hard push - worth looking at who the winners are and what the trade offs are.

mhb2• 3 years ago

That and gas stoves bad.

rootusrootus4• 3 years ago

The 'gas stoves bad' movement isn't a push, it's a pull.

MrMan• 3 years ago

gas stoves are bad

mhb2• 3 years ago

Google Trends: "heat pump", "gas stove":

https://trends.google.com/trends/explore?date=2021-01-10%202...

JTbane• 3 years ago

Gas stoves bad, yes. If you do a modicum of research you can see that they cause indoor air pollution (and most people don't have real hood vents to outside the building).

snuxoll5• 3 years ago

The whole bit about gas stoves I have no doubt is a pretty typical astroturf campaign from the fossil fuel industry. They have shamelessly made up pro-gas nonprofits using fake personas, paid social media influencers to promote gas stovetops, and are likely behind the current "gubmit wants to take away your gas stove" trend that's drumming up online drama.

One doesn't even need to look at climate impact to say gas stoves are bad, but focus the narrative on that one aspect and you can get climate deniers hyperventilating and defending their gas stovetop with statements like "you'll pry my gas stove from my dead hands". But really, economics are going to kill them all the same - induction stoves are dramatically more energy efficient, have the same benefits of fast thermal response, and don't pose a gigantic risk to life and limb every time you turn them on (or leave them off, for that matter).

nicoburns5• 3 years ago

Is there a global push to get everyone to switch to heat pumps.

I mean, yes. They're much more energy efficient than the alternatives and will play a key part of removing our dependence on fossil fuels.

I understand that its for climate benefits but it feels very coordinated.

That seems like a good thing?

nashashmi6• 3 years ago

They are not more energy efficient than burning gas.

Edit: since i am getting downvoted to oblivion, let me fight back here. I genuinely wished heat pumps would be more efficient and in theory they can be. I would love to not generate heat and just use the outside heat energy and compress it down into a smaller location.

But compressing and decompressing is not an energy efficient task. It takes a lot of work. Mechanical inefficiencies are a huge energy consumption. Gas is simply burning fuel. Yes, we should save gas for rainy days. But I hate to say that it is more efficient and cheap. There is no comparison.

vintermann2• 3 years ago

Yeah. If some people came together at Davos or whatever and decided "we need to promote heat pumps!", you can be sure they would mess it up. Consent can maybe be manufactured. Enthusiasm is organic, for good and bad.

kzrdude2• 3 years ago

Who do you imagine is pushing, and why?

Don't you want to resist to turn to explanations like this, that require some invisible force to pull the strings? I think there are more realistic ways to imagine this happening.

If for example a pop star is getting a lot of attention, in multiple countries, what is the mechanism behind that? And is it orchestrated?

suoduandao22• 3 years ago

Explanations like what? Op didn’t put forward much in the way of hypotheses. If you have a good explanation of the mechanism by which attention accumulates around topics that doesn’t require orchestration it would be interesting to hear, it seems like a poorly understood phenomenon.

jjtheblunt2• 3 years ago

Wait till we have Heat Pumps built with Rust!

But seriously i think it’s just that awareness hit a critical threshold so the hysteresis kicks in and articles proliferate. In both cases.

PaulDavisThe1st• 3 years ago

There's really no question that Rust will undoubtedly take over most heat pumps, sooner or later.

nashashmi6• 3 years ago

Heat pumps are the opposite of AC. AC industry is behind this for sure. It is like a paid PR campaign. It is not more economical then gas. So now gas is going to be punished for factors X,Y,Z.

It is coordinated. I wish there is more investigative research into who and why they are doing this.

mikeyouse8• 3 years ago

Ah yes, "big AC" is bullying the Oil and Gas industry with their subversive marketing. If only Exxon, BP, and Shell had some political clout they could expose this plot.

jamiek88• 3 years ago

In this thread you’ve gone form ‘compressors don’t work like that’ to ‘this is all a conspiracy by big A/C’.

You are not engaging with any of the helpful, generous replies, in fact going as far as to say that you wish you could call it ‘coordinated’.

Why are you even here if you think we are all lying shill for big air compressor?

WatchdogReset10• 3 years ago

For the record, I am only trying to make my elearning website more known. There is plenty of other HVAC subject that I would like to share. It's just that Heat Pump where for me an interesting topics to get into the subject but you can have a look at other free courses.

practice9• 3 years ago

The reason is that suddenly everybody understood that Russia is an unreliable partner for their countries energy needs (at least in Europe).

For consumers it's also became clear that being slightly more independent from centralized heating and/or energy infrastructure is a good thing

manojlds• 3 years ago

Suddenly, as in Crimea didn't happen?

dahfizz• 3 years ago

A more plausible explanation is that the we HN-ers are a bunch of nerds and heatpumps are excellent nerd-bait

micromacrofoot2• 3 years ago

It's a great way to lessen the demand on fossil fuels and the power grid.

Manufacturers are obviously pushing, but many utility companies and municipalities are too. Basically the electric car or solar panels of HVAC. It's one of those things where there are a lot of incentives for everyone involved all the way down the line.

hexmiles• 3 years ago

I don't know if it applies everywhere, but two factor come to mind: the (somewhat recent) change in energy and gas price did make heat pump a lot more competitive with more traditional heating solutions, and recently there are a lot of economic incentives (at least, here in Europe) to renovate house for energy efficiency, which make solar panel and heat pump very attractive.

masklinn2• 3 years ago

and recently there are a lot of economic incentives (at least, here in Europe) to renovate house for energy efficiency, which make solar panel and heat pump very attractive.

Economic but also legal and geopolitical: fuel oil furnaces are getting restricted or banned, and the combination of climate change, air quality standards, and russian instability makes gas look at lot worse than it did 10 or 20 years back.

wongarsu2• 3 years ago

For a long time the main problem of heat pumps was that while they are more efficient, a kilowatthour of gas or oil is much cheaper than a kilowatthour of electricity. But in the last two years natural gas prizes have gone crazy, removing that price disadvantage.

Of course heat pumps emitting no particulates and being able to run on renewables are also good reasons, especially as the health impact of living in cities with high PM2.5 values becomes clearer. But I don't think those are the primary drivers.

PragmaticPulp4• 3 years ago

Heat pump technology has also improved significantly. You can now buy heat pumps that remain efficient down to very low temperatures, which makes them appropriate for a larger range of climates now.

Many models are in very high demand. Some of the units I looked at recently were back ordered so far that I was told to pick something else if I expected to have it within the year.

The demand is very high because the technology is good. It’s not a campaign or conspiracy.

mytailorisrich2• 3 years ago

It's not directly related to the recent spike in prices, especially considering that a heat pump installation is very expensive in itself and potentially disruptive.

Rather, it's a combination wanting to get to net zero, so no emissions, with the big problem of generating enough green electricity. A heat pump system has no emissions and consumes much less electricity than an electric boiler/electric heater.

oceanplexian• 3 years ago

An overlooked benefit is that they actually improve comfort over a boiler in a dry climate, so if you live somewhere with low humidity they help keep the air less dry. They also give you heating and cooling.. for places that don’t have Air Conditioning it’s a worthwhile upgrade.

quickthrowman• 3 years ago

NG (in the US) is now about 70-80% cheaper than it was at the recent highs.

atoav• 3 years ago

My father has solar and a heat pump. His cummulative heating and electrical cost is practically zero over the year. On many days the solor panels produce more than he can use so he gets money for feeding it into the grid.

If the roof of your house produces enough electricity for the people living it and the heating (and cooling) of all rooms, it is a no brainer to switch to a form of heating that relies on electricity.

helen___keller2• 3 years ago

I’ve been independently interested in heat pumps because I need to replace my old end-of-life system and I’ve been interested if a modern cold-weather mini split system is a better investment. There’s lots of conflicting info I’ve found on if heat pumps perform in freezing weather and at what kind of efficiency.

I’m sure there’s others in my position.

fullstop7• 3 years ago

Where do you live geographically? I'm in eastern Pennsylvania and have lived with a heat pump for 20+ years.

sbradford269• 3 years ago

So largely I think the confusion stems from there being two major different "types" of heat pumps and they perform very differently.

The first is your conventional type system, this is usually what AC units are in the US. They run at maybe 1 or 2 speeds. These type of heat pumps are common in the southern parts of the US but also will be found paired with a gas furnace in the northern US. Since they don't adjust their output dynamically they tend to start losing capacity/efficiency significantly around 25-30F.

The second is an inverter driven heat pump. You usually find these in mini splits but they can also be found in a standard air handler form factor that would replace a furnace. The inverter allows the compressor to adjust based on demand and exterior temperature to maximize efficiency. This allow these units to operate efficiently down to -13F depending on the unit. Now there will still be some capacity loss at those temps so during the design of the system this has to be taken into account.

For detailed information on the efficiency of heat pumps I would check out NEEPs website. It is a great resource, it will show you capacity and efficiency (COP) of tons of different units across their operating temperatures.

https://ashp.neep.org/

kwhitefoot• 3 years ago

Heat pumps sold in Norway are claimed to work down to -30°C. See, for instance, the Samsung Nordic Extreme: https://www.elkjop.no/product/hjem-rengjoring-og-kjokkenutst...

I don't know what the coefficient of performance is at that temperature though.

rayiner• 3 years ago

I’ve got a mid-range Amana heat pump and even that has a COP of 2.1 (2 watts of heating per watt used) down to 0F.

Heat pumps require different system design than a traditional setup, where the cooling load is usually the driving force. You might need a bigger heat pump to handle the heating load in very cold weather accounting for the efficiency loss.

mr_mitm• 3 years ago

You should expect this impression to become more intense. How else will you heat your home without emitting greenhouse gasses? Electric space heaters are vastly inferior for obvious reasons. Everything else is out because we eventually need to achieve (net) zero emissions. And since there are a lot of gas and oil heaters to be replaced, heat pumps will only increase in demand.

Maxburn4• 3 years ago

YES. There is a massive electrification push right now because electric items can be fed from "sustainable" things like wind/dam/solar and don't emit CO or CO2 in operation.

Heat pumps are also inexpensive on initial cost and less expensive than straight AC with gas heat.

They are also low maintenance in comparison to straight AC with gas heat.

Very popular units in southern US.

bcrosby95• 3 years ago

This hasn't been my experience. I can get an AC unit and gas furnace installed for something like 7k. But a heat pump unit that heats and cools is something like 13k installed. I obviously went with the former.

notdarkyet• 3 years ago

I see this as well and it looks to be multiple people buying in to the campaign, especially here on HN.

Having lived in a new, high end apartment that had a heat pump for both heating and cooling for 3 years, I am very unimpressed with the tech. Running nonstop, couldn't heat/cool above/below a certain threshold. Electric bill very high. Clogged and broke a lot. If the general radiant heat and cooling from being in large building didn't exist, I couldn't see this working halfway decent in any place in the midwest. This might work for areas with less variable temperature ranges but for the midwest USA, not seeing it.

fullstop7• 3 years ago

Your high end apartment must have had a low end heat pump installed.

In the midwest a geothermal heat pump would work wonderfully.

Also, they are designed to run constantly in order to maintain the set temperature -- it's not like a natural gas fired furnace where it quickly reaches the set point.

LazyMans5• 3 years ago

This is not the common experience, it's just an AC that runs in reverse. It sounds like a bad install/bad equipment.

PragmaticPulp4• 3 years ago

Your singular experience is an outlier, not an example of totally normal circumstances.

There is no conspiracy to push broken technology on to the masses. Heat pump technology has come a long way and modern heat pumps are very good at what they do.

If someone installed a heat pump that doesn’t work in the temperature range of your location, they really screwed up. Modern heat pumps can be selected to work down to very low temperatures, and they’re installed with auxiliary heat when necessary. The design parameters aren’t a mystery.

flakeoil• 3 years ago

Also remember that air-to-air heat pumps are overall less efficient and powerful than air-to-water or geothermal-to-water type heat pumps.

Firstly the later typically have a higher power rating.

Secondly, if you can lead water around the house and heat via radiators or floor heating you get a much better efficiency.

rgmerk3• 3 years ago

Have you considered that you bought the heat pump equivalent of a Ford Edsel, rather than the tech being fundamentally bad?

Lutger• 3 years ago

Just the hivemind I guess, doesn't feel coordinated to me but rather obvious. In my country the waiting time for heat pumps is now over a year. People can't stop talking about energy, the war and their utility bills. Heat pumps are very on topic.

Any reasons to change my mind?

rhussmann• 3 years ago

At least in NYC, new installations of gas and oil boilers for building and water heating will be regulated away in favor of electric-heating means (like heat pumps) by 2025: https://www.silive.com/news/2022/12/new-yorks-new-roadmap-to...

This is, of course, the regulation as it stands today; things can always change. Additionally NYC alone likely doesn't account for the attention. But, other metros and municipalities could have similar legislation.

redeeman• 3 years ago

topic of discussion: is anyone else concerned that all the new things being clearly pushed hard, regardless of reasons(good or bad), has the common theme of centralizing. In a world where if your heatpump stops working, you die from cold, it would be an awfully sad thing if social credit scores dictated a very low kilowatthour limit. Much more sad than a world where you obtain firewood from some local vendor

kevstev3• 3 years ago

I am not sure the case you are making here- most people who would be switching to a heat pump for heat are almost certainly using oil, natural gas, or propane to heat their homes, all of which require a good deal of centralization.

Those that have the ability to use firewood to heat their homes today can continue doing so if they need to- its not a requirement to close up your chimney permanently to use one.

FWIW I am considering switching to a heat pump, but would still have natural gas fireplaces as a backup.

PragmaticPulp4• 3 years ago

has the common theme of centralizing. In a world where if your heatpump stops working, you die from cold,

Using machinery for heating isn’t new. Virtually nobody in the modern world uses firewood from a local vendor to heat their homes.

These conspiracy theorist angles are baffling. Heat pumps are just another variation of AC, which is already ubiquitous. If people don’t use heat pumps, they won’t use firewood. They’ll use a regular furnace or electric heat.

pjc502• 3 years ago

Much more sad than a world where you obtain firewood from some local vendor

A while ago I ran the numbers, and to meet UK electricity demand from wood would consume every single tree in the country in three months.

Limiting that to heating and giving up on industry would stretch that a bit, but the country is fundamentally dependent on imports to stay alive. We can't not be global.

micromacrofoot2• 3 years ago

They could also just shut off your gas, heat pumps introduce no newfound ability to be authoritarian that isn't already there.

triceratops3• 3 years ago

Did you know that installing a heat pump doesn't magically cause fireplaces in the house to stop working? Or that if you're concerned about being cut off from electricity because of your low "social credit score" the heat pump will run just fine off solar panels and batteries?

adrianN• 3 years ago

Yeah, if we could only cut down our population by 20x or so in order to make firewood sustainable again, that would really show Big-Heatpump /s.

mschuster91• 3 years ago

Clearly there is a push.

Yeah, tl;dr: fuel price scares and the French nuclear power plant disaster, as well as government regulations.

To expand: most homes traditionally are heated by either burning something fossil (oil, gas, coal), somewhat half-ish renewable (wood pellets, straight chopped wood), by straight electricity (resistive heating) or by heat pumps (air-to-air, ground-to-air, deep-well-to-air aka geothermal). Some homes particularly in urban areas or in close proximity to a large power plant can also be heated by district heating using one of the aforementioned heat sources.

And all of these classes of heaters have their issues:

- Electricity is the easiest of the bunch from a technical point of view, but you're out of luck when the grid fails for whatever reason, you're tied to grid price hikes in some contract models (as people learned the hard way in Texas' last winter spike), there will be fuel burned as part of the generation and frankly resistive heating is wasteful.

- Wood pellet has the problem that the amount of waste (=sawdust) is finite, which means you're chopping down wood that could be used for construction and burning it instead. That is a waste of money and valuable resources when wood is scarce, fine particulate matter causes smell and health issues, and a lot of wood is unethically sourced.

- Solid-wood or coal heaters are difficult to properly fire up - most people fire it wrong (not enough oxygen / too much fuel load), resulting in higher consumption of wood, higher emissions and a danger of soot buildup which is a fire risk. Additionally, many home fires are started by people disposing not-completely-cooled ash or placing flammable objects too close to the oven or exhaust, and still a lot of people die because of carbon monoxide emissions caused by improper handling.

- Oil stinks to hell and beyond, the boilers need an insane amount of maintenance so they don't clog up, you need to ship tanker trucks to homes, there are risks of spillage and contamination, and the same emissions issues of wood apply (plus, oil generates more CO2 than gas per kWh of heat). Also, it's not renewable at all.

- Gas is relatively easy to ship around when there is a gas distribution network in place, it burns relatively clean, but carries an explosion risk and is fossil in origin (at least for the next decades that it will take to build up power-to-gas infrastructure).

In contrast, heat pumps are pretty awesome:

- all they need is a bit of electricity - a good heat pump can achieve up to 4x ratio, meaning it generates 4 kWh of available heat in the home by using 1 kWh of electricity. That also makes off-grid or local generator fallback solutions more feasible - a 20 kW heat-pump boiler needs a 5 kW generator which can be had for a couple hundred dollars instead of a massive generator unit.

- their heat sources (or rather, cold sinks) are renewable - air, local ground loops or deep wells are virtually infinite. That means, as long as your electricity supply is renewable, your heat generation also is renewable.

- Most heat pumps run at 40-ish degrees. That in turn prohibits the use of old-school convection radiators, so most installations with heat pumps tend to use floor heating which needs less energy to achieve a temperature comfortable for humans (our feet are the most sensitive part, but as heat from a convection radiator rises to the top of the room, it needs a lot of energy for a comfortably warm floor).

- they are, particularly when compared to oil heating, extremely small and don't cause emissions

- they don't need much maintenance effort to keep running, and no need for chimney sweepers either

- they don't pose an imminent risk of carbon monoxide poisoning or outright fire

Basically, the only issue heat pumps have is you need specially trained people to install them and they are short in supply at the moment since everyone and their dog got shocked to heaven in the last year of that goddamn war and heat pumps are the objectively best way to heat a home.

scythe3• 3 years ago

I'm just annoyed that I was talking about heat pumps for the last five years or so and nobody is giving me any credit for running an international conspiracy.

But seriously, it's just the next fish to fry after electric vehicles became a solved problem. Heating buildings is somewhere around 10-25% of total emissions and probably the largest remaining single factor not directly addressed by switching the electric grid to renewables, so many people concerned about climate change have converged on it.

achenatx• 3 years ago

my friend is building his house and is putting in 4 heat pumps (big house). The problem is we just lost power for 4 days and 2 years ago we lost power for 5 days. He is discovering that electric heat uses massive amounts of electricity and there is no way to get a residential generator big enough to power them all. He might not even be able to power one (they can use in excess of 20kw).

I would never get electrical water heater, stove, and heater for that reason.

boringg4• 3 years ago

So this is one of my big concerns - I live in a cold weather country currently. We have power outages once every couple of years. If I don't have back up power my pipes freeze and then i'm out probably > $50k.

I was thinking the solution for me is to put in a heat pump and then run a backup gas generator. But that solution feels like a significant amount of overbuild. I have 3 minisplits already but they aren't valuable in the winter -- where you install your AC units isn't where you would install your heating units .. I.e. the top of my house for AC, the bottom of the house for heat.

Having multiple energy sources to defray risk is helpful.

thekingshorses• 3 years ago

If there is a power outage, you can't run your natural gas heater either. It needs fan to run.

danans2• 3 years ago

my friend is building his house and is putting in 4 heat pumps (big house). The problem is we just lost power for 4 days and 2 years ago we lost power for 5 days. He is discovering that electric heat uses massive amounts of electricity and there is no way to get a residential generator big enough to power them all. He might not even be able to power one (they can use in excess of 20kw).

If he's building the house new, he should strongly consider investing in designing the building envelope in a way that 20kW heat pumps aren't required. It's very possible, especially with new builds.

The models to follow are Passive House [1] and Pretty Good House [2]. There are many examples of large houses built to those standards in cold climates that use a heat pump that only draws 2kW, which could easily be powered by a generator or backup battery. This assumes that by "big house" we mean something still below ~3500sqft and not some kind of mansion.

The basics are to get the building air leakage below 1ACH50 (3-5x better than most codes, but not hard in a new build), and eliminate thermal bridging by using thick exterior insulation around the building perimeter.

1. https://passivehouse.com/

2. https://www.prettygoodhouse.org/

Silverback_VII• 3 years ago

preparations for nuclear winter.

bilsbie3• 3 years ago

Easier to turn off people’s electric than gas when they don’t follow the social rules.

timbit426• 3 years ago

Not when they have solar.

burkaman• 3 years ago

Yes, there is currently a coordinated push by the entire world to prevent excessive climate change.

kavalg• 3 years ago

I am a happy user of a DYI air source heat pump, that I've been using for 8+ years, mostly for heating in a residential building.

First, it must be told that an off the shelf AC unit is technically speaking also a heat pump. There has been this distinction (and confusion) between AC units and (mostly) ground source heat pumps because, you know the latter actually have a water 'pump' to circulate fluid in the ground piping. Ground source heat pumps are far more expensive that AC units and are nearly impossible to retrofit in existing buildings. Hence, companies came up with a 'middle ground' solution, called air source heat pumps. In these devices the outdoor unit is much like an outdoor unit of a split type AC, but the indoor unit is basically a refrigerant/water heat exchanger with a water pump and some sensors around it. There is also a monoblock type of air source heat pump, where all components are in the outer block and you only connect the piping.

IMHO, the reason air source heat pumps are becoming popular now is because their price went down considerably during the last 5 years, whereas the price of fossil fuel heat sources has gone up. Back then when I had to choose between a gas boiler and a heat pump, the boiler was around EUR 2, off the shelf heat pump (24000 btu) was around EUR 7k and for the DIY option I paid a total of EUR 2.3k. The reason for this was that the market for air source heat pumps was underdeveloped and companies (e.g. Mitsubishi, Daikin, Fujitsu) were charging a lot more in this market segment (rich people with new houses). At some point in time, people started realizing the benefits of a heat pump over a normal AC (less units, no noise, nor air currents, better efficiency, can produce hot water, heating is decoupled from the source and more sources, such as solar can be seamlessly plugged in). Manufacturers albeit slowly responded to this demand.

Now with solar power gaining more traction, they are becoming a very obvious choice.

elil176• 3 years ago

Well of course it is being pushed, though I would not necessarily call it coordinated.

Companies that sell heat pumps are advertising hard. It's an easy sell for them with rising gas prices.

The US government is "pushing them" by offering tax credits for heat pump systems. This is part of a plan to reduce pollution, improve energy independence/energy security, and save citizens money on their heating bills. No secret there - politicians and public servants are excited about this and they are talking about it. They are also offering tax credits for other high efficiency heating systems, but not that many people are looking at those tax credits because buying a new high efficiency gas furnace doesn't make that much sense when you could buy a more efficient heat pump instead.

Many individual people are also talking about them because they are a great way to help the environment and save money at the same time.

And I think a lot of people just think they are cool technology as well.

boringg4• 3 years ago

I think this is probably the right answer. It keeps popping up everywhere.

I'm always a skeptic on when something gets super hyped. In this case it's more use-case specific that makes me skeptical - majority of people its 100% fit.

billjings2• 3 years ago

Here's a couple of reasons:

1. The American market has a lot of incorrect perceptions of heat pumps. Debunking these makes for great viral content! 2. The IRA introduced big incentives for various electrification expenses.

The incentives are the big thing, but the public interest/controversy part is why some enhancements like heat pumps and kitchen electrification ("don't take away my gas stove!") are going more viral than, say, electric vehicles (technology connections guy has some good EV content, but it's not doing quite the same numbers)

sophacles3• 3 years ago

What is IRA in this context? I don't think heat pumps have anything to do with retirement nor the political status of Norther Ireland.

heisenbit• 3 years ago

Continuous improvements in technology, growth spurt in electric motors, demand gap for automobile motor part suppliers having to seek out related industries, cheap summer electricity via solar panel meet kick in the behind by fossil fuel energy prices.

dsfyu404ed• 3 years ago

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push.

Based on the lack of political dick swinging I don't think this is a "push". They're legitimately good technology for certain use cases, I'm sure the manufacturers are pushing them. They are also The New Hotness(TM) and they are billed as environmentally friendly. Both those attributes are valuable by themselves to some people.

I think this is more a case of a grassroots-originated circle jerk within certain demographic bubbles.

I get a lot of "air fryer" vibe from the whole thing. And I say this as someone who owns and really likes his air fryer.

peterhunt3• 3 years ago

It is coordinated. In many states there are huge incentives [1] to disconnect your existing home from (and not connect new construction to) the natural gas infrastructure.

This is great for the climate but air source heat pump technology simply doesn't work well in cold climates. Most heat pumps in the United States have 100% efficiency down to about 20 degrees F. Below that they "lose efficiency."

What most people don't realize is that "lose efficiency" = blows cool or cold air. So if you live somewhere that routinely gets that low you are likely either going to be really cold, or have to engage aux heat (often natgas or oil-based heating or electric resistance heating).

Additionally, even when operating at 100% efficiency they don't blow air as hot as traditional heating sources. So if you have a poorly insulated room, large space, or even just an unusually cold day, it will often have a hard time keeping up.

I have found that I only use my air source heat pump a little bit during the fall in New England, and I have to run aux heat throughout basically all of winter. Talking to my friends in the region who have heat pumps, they all have similar experiences.

I think we are all very eager to get off of fossil fuels but the technology just isn't there yet, and I am concerned that most people installing heat pumps today don't know the risks associated with them in extreme weather events. If your heat pump can't keep up and you didn't install aux heating you can't live in your house, your pipes will freeze, and you will generally have a bad time. If you did install and use aux heating, you may be surprised at how expensive and inefficient resistive electric heating is as it may need to run all the time.

[1] Massachusetts will pay you $10k to install air source heat pumps and disconnect from natural gas https://www.masssave.com/en/residential/rebates-and-incentiv...

nicpottier2• 3 years ago

This is FUD. I live in climate zone 5 in a 100 year old house that has high heating demands and our air source heat pump has been awesome, even when it dipped into the negatives briefly this year. Our heat pump is over 100% efficient down to 0F.

snozolli3• 3 years ago

Most heat pumps in the United States have 100% efficiency down to about 20 degrees F. Below that they "lose efficiency."

Most things that are already installed are worse than the latest technology that's available.

That's not an argument against the latest technology.

kodt2• 3 years ago

1. There was recently a statement released by a member of the Consumer Product Safety Commission saying they were considering regulating indoor pollution from natural gas stoves. This lead to a bunch of outrage and claims that Natural Gas was going to be banned at a Federal level. https://www.washingtonpost.com/climate-environment/2023/01/1...

2. Cites like NYC have implemented bans or limits on new gas installations, and it has been proposed at the state level as well. Other cities such as Chicago have had conversations regarding this issue, at least enough for it to get into the news and spark minor outrage.

Because of these recent controversies there has been much talk about Heat Pumps and whether or not they are able to function efficiently or sufficiently in sub zero temperatures regularly seen in the upper Midwest or North East.

danans2• 3 years ago

worth looking at who the winners are and what the trade offs are.

The winners are consumers, the effort to reduce GHG and particulate emissions, and the drive toward energy independence (whether at the national, local, or hyper-local level).

The losers are fossil fuel extraction industries, because due to the high COP of heat pumps, far more heat is delivered per unit of energy consumed, even if that energy ultimately comes from burning natural gas at a power station. Also, the source of the energy itself gets disintermediated, since electricity can come from multiple sources, including renewables.

The tradeoffs are (for now): Higher upfront installation cost (tempered by the IRA, and potentially lower operating costs), availability of the equipment (supply chain stuff), and long delays in installation due to lack of qualified installers (and resulting high costs).

guidoism3• 3 years ago

It would be great if this was coordinated. Ideas that are good for people usually don't get a very intelligent effort promoting them compared to really bad ideas that make a few people really rich.

WatchdogReset10• 3 years ago

My two cents, I just tried to show this free course on my site, because heat pumps are an interesting topic. There is also others courses like this : https://hvac-learning.com/courses/air-handling-units-technol...

Heat pump as every heating or cooling devices, have pro and cons. This is where HVAC knowledge is nice to have, in order to have the best solutions. For example, the maintenance / obsolescence are an under estimated point when it comes to environment and savings

rgmerk3• 3 years ago

Governments are influenced by what other governments are doing in a variety of ways.

At a basic level, governments are full of people who have an interest in public policy, and they read publications that cover public policy matters from around the world. If the EU brings in a policy that encourages an expansion in heat pump usage, it'll probably get written up in The Economist (and a bunch of more specialised publications), and, guess what, bureaucrats and political staffers in the UK, the US, Canada and so on will read it.

There are also institutions specifically devoted to developing policy advice for national governments, and in the renewable energy space the big one is IRENA. And guess what, they're telling their member governments that, hey, if you want to screw over the Russians, meet your greenhouse targets, and save your citizens a bunch of money, heat pumps are the way to go. And as those things happen to be basically true, national governments are falling over themselves to implement policies to encourage it to happen.

beardyw• 3 years ago

Error establishing a database connection

WatchdogReset10• 3 years ago

The site is pretty new, I(admin) am not used to have lots of traffic. I will analyze what happened and chose better solution. I am sorry for the inconvenience !

Bhilai• 3 years ago

Definitely a lot of posts about heat pumps on HN recently that this topic has piqued my interest but only to the point that I want to know if I can install one in my home. Are there any legit resources out there that can help me understand if heat pump is a right choice for my home based on Geo, type of home, sqft and other factors to consider before replacing current systems (two ACs and two furnaces?)

hcknwscommenter2• 3 years ago

My $0.02 are that any competent and honest HVAC company will be able to walk you through the concepts of your home's heating/cooling load etc. and what size heat pump can meet that need, what it costs to run annually, and what incentives there are. It's not that hard. I would reach out to three highly ranked (or word of mouth suggested) HVAC co's and start the conversation.

rapsey2• 3 years ago

I guess they are a new thing in the US. In Europe installing a heat pump with floor heating is done for practically every new family house. It is the cheapest (for us) and nicest way to heat up your home. Though very few people build houses out of wood, unlike the US.

gautamcgoel• 3 years ago

What are the houses usually made of? Stone?

gwbas1c2• 3 years ago

Generally, they can work anywhere in the continental US. (Assuming you live in the US.) If you're in northern NH, NY, VT, or Maine, you might want to keep your gas system as a backup. (New homes tend to have electric backup, but if you have an older home they just keep your furnace as backup.)

I have a 3000 sqft house in MA with a heat pump as my primary heat, and an electric strip as backup. The heat pump goes into the ductwork for most of the house. I generally haven't had problems. (It did have to be adjusted because it was the first time the installer put one in.) I have solar and usually get 1-2 large bills in January and February, and then March and April are very cheap, if I get a bill at all. My "large" January and February are comparable to what I'd spend on conventional heat.

Last weekend we had a "once in a century" cold snap down to -4. Most of the house was at temp, but one room fell to the high 50s. From what I've heard, plenty of people with conventional heat had far worse issues than a chilly room.

kodt2• 3 years ago

North Dakota and Minnesota are on average colder than the states you listed. I would also include Montana, Wisconsin, Wyoming, and Idaho as states where you should be concerned about performance in sub zero temperatures and have a backup heat source.

robotpony• 3 years ago

Around Vancouver our heat pump has performed adequately even down to -15C/5F. This may be related to it being a deep ground loop geothermal setup (vertical instead of horizontal), and the type of building (concrete). We do have a gas fireplace as backup, but have not needed it at the temperatures we see in this corner of the world.

kevstev3• 3 years ago

If you already have a central AC system, a heat pump is more or less a drop in replacement. The heat pump becomes both your heat and AC unit.

Heat pumps are now the most premium option on units offered by the well known names in HVAC- Trane, Carrier, etc.

In terms of suitability for your climate, they should work just fine for most people- they start to struggle if you are in an area when temps get down to about 10 degrees Farenheit, though they improve in this area each year. Even if you live in an area that cold, there are options to mitigate this- leaving your current furnace hooked up to be turned on during those cold periods, etc. What it comes down to is it just gets more expensive if you live in these colder areas, but over time the energy savings should give you a return on your investment in less than ten years.

My Air conditioner blew this fall, so I am actively in the process of getting bids for heat pumps.

timerol4• 3 years ago

What climate zone are you in? (assuming US) https://learnmetrics.com/wp-content/uploads/hspf4-and-hspf5-...

If you're in 1, 2, or 3, heat pumps are definitely the right option. In zone 4 or 5, newer cold temperature heat pumps are a good idea. In 6, 7, or 8 it's less of a sure thing, and you will likely want a backup source for the colder days.

kebman2• 3 years ago

Looks like the HN posting crashed the site.

WatchdogReset10• 3 years ago

The site is pretty new, I am the webmaster, maybe I should analyze the log and choose better hosting. I am sorry about the inconvenience!

kebman2• 3 years ago

No worries, I'll take a look at your site later. :) If it helps, I tried reaching the site from Norway. Thanks for reaching out! Edit: It works just fine now! Looks pretty interesting!

asow922• 3 years ago

As someone who lives in the northeast and has a 3600sqft home, I'm wondering how many heat pumps it would take to replace my gas steam boiler system. I'm not sure if heat pumps would be cost efficient given those parameters.

prottog3• 3 years ago

In the Northeast with that much square footage, you would be better off with ground-source heat pumps (whether open or closed loop), rather than the normal air-source heat pumps.

asow922• 3 years ago

I guess the concern I have with all this is that my current system works well, and I don't want to spend $10K+ unless it brings down my heating costs significantly. Could a ground-source heat pump system do that?

elil176• 3 years ago

One* heat pump will do fine, but you might need a low temperature heat pump depending on where you are. After you factor in that gas is cheaper than electricity per kWh, the system should save you money as long as it is running at an efficiency higher than ~130%.

A contractor should be able to select an appropriate system for you, but if you want to do it yourself, look for yourself, get the 2021 ASHRAE climatic design conditions for your area and choose a heat pump with a minimum operating temperature which is lower than the coldest month 99.6% heating drybulb temperature (DB) (should be the top row, left most temperature).

*You would also need a fairly large heat pump, perhaps 7 tons (tons here means tons of refrigeration, or how many tons of ice the system can melt per day) depending on how well insulated you are.

chem83• 3 years ago

I’ve had Mitsubishi heat pumps in a condo in the northeast for 3 years and they’ve worked great. No other heating sources here. I keep them on all day, which the mfgt discourages. My main gripe was their kumo cloud and Wi-Fi connectivity but they’ve since fixed firmware and the cloud side and it works much better.

YellowTech• 3 years ago

Seems like OP just performed a stress test on his website as he is the "Webmaster of https://hvac-learning.com an HVAC elearning website"[1]. Hopefully you can figure out something! Thank you for educating about such technology!

[1] from WatchdogReset's profile about

WatchdogReset10• 3 years ago

I am sorry for the inconvenience. I am still learning how to build a nice and efficient website. I will analyze what happened and try to fix and enhance !

scrollaway2• 3 years ago

I love that you're building free educational resources, especially about something like this! If you need help/advice to help build your website, email me (see my profile), I'll be delighted to help pro bono. :)

endisneigh3• 3 years ago

I wish, wish wish there was a portable mini split (not a portable air conditioner).

The closest thing is this:

https://rollibot.com/product/mini-split-ac-room-air-conditio...

but it sucks.

I don't understand why these things have to be permanent fixtures of your house, necessarily.

bilsbie3• 3 years ago

I’m confused what you’re asking for (and why) but it sounds interesting.

endisneigh3• 3 years ago

A portable machine to provide heat and cooling via heat pump technology.

For cooling this exists in many forms: there are the window air conditioners, and "portable" window air conditioners which have a duct that connects to the window. The problem with the latter is that they're loud and the ducts result in a lot of heat loss.

For heating there are some portable air conditioners that use a heat pump but they're subject to the same issue described above. More common is resistive electrical heat in the form of coils or an oil filled container that radiates heat.

A portable mini split, where it connects through the window would give you a similar advantage as a portable air conditioner, but with more efficiency and being less loud.

timerol4• 3 years ago

NYCHA is currently running a contest to develop a heat pump window unit. All of the proposed units are expensive to get those contest dollars, but should come down in price after.

https://www.gradientcomfort.com/pages/products-air-condition...

https://www.achrnews.com/articles/147122-midea-heat-pumps-to...

ctroein89• 3 years ago

I have two heat pump window air conditioners installed in my apartment, with cooling, heating and resistance electrical heating: https://www.frigidaire.com/Home-Comfort/Air-Conditioning/Win.... The problem is that the tech is so poorly advertised, that I had to double-check the specs on manufacturer's website that this model was, in fact, a heat pump. Most people don't know that heat pump window units already are an option.

I'd love for NYC to mandate that ACs must function as heat pumps: the additional parts are cheap, and as America's largest market for window AC units, the NYC market would force competition for much cheaper heat pump window units.

scythe3• 3 years ago

The issue is that cold should be supplied near the ceiling, while heat should be supplied near the floor. So this unit would need two separate terminals or suffer inadequate performance in one of the modes.

rr888• 3 years ago

I just dont like moving parts. My problem with heat pumps is that you have to replace every 10-20 years which seems wasteful.

kupopuffs• 3 years ago

Do you own a heater that has lasted more than 10 years?

bluGill4• 3 years ago

The furnace in my house is from 1970 and still works. I don't want to know how inefficient it is. (I just upgraded the insulation of the house, replacing the furnace is a future problem)

timbit426• 3 years ago

My heat pump has a CoP of 3 and paid for itself in 10 years. New heat pumps have a CoP of 4 or higher and might pay for themselves in less.

How much material in a heat pump is recyclable and how much isn't, compared to a furnace?

We are trying to reduce CO2 and methane in the atmosphere. Throwing away the non-recyclable parts of heat pumps isn't as big of a concern. Polluting the ground and water isn't even as big a concern. Certainly they are concerns, but they pale in comparison.

boringg4• 3 years ago

Oh I have a question for the community here about heat pumps. I have three mini splits that I use for AC but connecting them to a home hub is bananas amount of work and inconsistent (Mitsubishi brand). I wish there was a legitimately good, robust system to connect AC units to my smart thermostat (Ecobee) or even some of the other devices I have.

It still feels the wild west for home energy systems - and the costs are quite high for the value they provide.

mataug• 3 years ago

So far I've been happy with using the mysa ecosystem for my smart home. It works with Apple HomeKit, its had relatively good reliability and the team behind the product have been responsive when I do face issues.

https://shop-us.getmysa.com/products/mysa-ac

From a technical perspective its just a IR remote with a wifi connection and a touch UI, but for controlling mini-splits it works great in my home.

spikej• 3 years ago

Genuine question that I haven't been able to find a clear answer for: are heat pumps now different from air conditioners two to three decades ago? (other than the fact that they heat and cool)

Memory is fuzzy but I remember when I was a little kid and even captain planet cartoon showed air conditioners being bad for the environment...

Or is it that heat pumps are better than the fossil fuel counterparts and so if you're going to do something bad you might as well do something less bad?

Calvin02• 3 years ago

It is the latter.

Heat pumps are much better for the environment compared to the other sources of heating. Depending on where you live, you still need to heat your place and if so, heat pumps are better than other traditional methods like natural gas, wood, oil, or electricity.

Similar to air conditioning, if you want to minimize your impact on the climate, you could set your temperature lower in the winter and put on a few more layers and/or set the temperature higher in the summer to minimize your usage of heat pump/air conditioner. This puts less pressure on the grid and demand for electricity generation.

bagels• 3 years ago

Captain Planet is not a reliable source of information. Air conditioners use electricity, the generation of which can cause fossil fuels, but also can come from other sources.

ccooffee2• 3 years ago

even captain planet cartoon showed air conditioners being bad for the environment

That seems like it was a useful simplification for a children's cartoon, but things aren't that black-and-white.

1. Without air conditioning (or some other method of cooling and humidity control), almost all high-occupancy buildings would reduce their effectiveness as a work-place or living-place. OSHA has guidelines about office temperature (68-76, iirc), humidity, and overall air quality (e.g. pm2.5 levels).

2. The 1980s-era backlash against air conditioning was likely inspired by then-new knowledge about atmospheric ozone depletion. It was known that CFCs and bromine-containing compounds contribute to ozone depletion. It just so happens that CFC were common refrigerants (and aerosolizing agents). Refrigerant leaks from an air conditioner in those times released nasty stuff. CFCs are very rare (and restricted) in modern air conditioner / hvac systems. We instead use other chemicals which are not ozone depleters. (Though I believe that the theoretical performance of modern refrigerants is often not-as-good as the old CFCs.)

3. Running the air conditioner in a single family home is not terribly efficient, as (in most single family homes) most of the home is just empty space. Cooling bodies directly (e.g. cooling blankets, misting fans, etc) is more energy-efficient in these situations. Perhaps the more nuanced advice would be to use air conditioning to make the space "tolerable" but use direct cooling to make a space "comfortable". (This advice also applies to heating a space. I keep my thermostat between 60 and 65 and use blankets, small electrical resistance heaters, and drinking hot water as ways to temperature-regulate.)

scrollaway2• 3 years ago

Are cooling blankets a thing? Like, a not-a-scam thing?

energ8• 3 years ago

I have seen repeated claims of heat pump CoPs improving over decades. Can anyone summarize or provide links to what improvements are being made? Compressor technology? refrigerants? Fans to move heat? all of the above? Where is the path from here?

LazyMans5• 3 years ago

I can provide a likely incomplete summary of the improvements.

Compressors themselves have gotten much more energy efficient, although I'm not sure the impact on CoP is all that great since and waste heat from the compressor is being deposited in the home anyway. Variable speed compressors are the most efficient you can get pretty much.

Refrigerants have improved in someways, but not really in others. Since heat pumps could be running with exterior temperatures that are quite low, with the system under pressure, some refrigerant blends would have less than desirable vapor pressures leading to problems running in very low temperature conditions. For the most part, the changes to refrigerant blends have been related to their Global Warming Potential (GWP).

Expansion valves are a very important piece of a refrigerant loop, these used to be fixed orifaces. Nowadays these are dynamic, meaning they can increase efficiency of the system by metering the flow based on system load and other characteristics. These are called TXVs or Thermostatic Expansion Valves. Electronically controlled expansion valves are now hitting the market further increasing efficiency.

Finally there is the design of the interior and exterior coils. I dont think materials have changed much, but the surface area has changed. You may noticed a 2 ton unit from 1997 is about 1/4th the size of a 2 ton unit from 2022. More surface area on the coil for the exterior unit lets you extract more heat from the air without burning a ton of energy running the fan super hard.

Interior air handlers have probably improved some as well, variable speed motors, etc. Variable speed really is nice because you can get much more consistent temperatures in the home and wont get blasted in the face with heat from vents when a regular system cycles on and off.

Freestyler_3• 3 years ago

refrigerants (though some regulations have negative impact on this), Optimizing (DC motors and computers with sensors figuring out what is the best setting), Absorbing waste heat from the process, Insulation, Materials that stay more clean or self clean.

molsongolden• 3 years ago

Calvin (Segment) and Baker (Plaid) also recently put together a nice up-to-date heat pump info page and a heat pump vs. existing HVAC calculator.

https://heatpumpshooray.com/ https://calv.info/heat-pumps

raldi• 3 years ago

What do you mean by Segment and Plaid?

kaveet• 3 years ago

Calvin French-Owen is the founder of Segment and Baker Shogry was Head of Product at Plaid until recently.

hbarka• 3 years ago

It's worth mentioning that there are many heat pump makers now using CO2 as the refrigerant versus the older environmentally harmful ones.

vladgur2• 3 years ago

I live in SF Bay Area 20 minutes south of SF and I don’t have and don’t need A/C, so my HVAC needs are met by a gas furnace that is 10-15 years old at this point but it still works.

Another caveat is our electricity ranges from 30 to 35 cents per KWh and is probably second to Hawaii in terms of cost.

So I do check the cost of operating a Heatpump in the winter and due to high cost of power I am sticking with our gas furnace.

If and when I go solar, I may reconsider, but for now gas is simply cheaper

ericpauley• 3 years ago

As high as that is, it looks like the price of gas in SF is (relatively) even higher. $4.50 a therm per Google, or $0.15/kWh. A heat pump would only need a COP of 35/15=2.33 to be a better deal (very likely since it will never be that cold in SF, and you get air conditioning for the very few days you might want it).

stavros• 3 years ago

As the Technology Connections video linked here mentions, "if it’s more expensive to use the option that saves energy... that’s a problem".

liminalsunset• 3 years ago

TL;DR a heat pump isn't worth it in Vancouver, BC, for me anyway.

As a counterpoint to what seems to me like extremely high rates for electricity, as of right now in Vancouver, BC, Canada, I recently calculated that a heat pump would cost about ~2.5-3.5 cents per kWh of heat energy vs ~4.5 cents for gas heating at 80% efficiency. Power on average is about $0.10 USD per kWh here and gas is about $10 USD per GJ.

The average house here uses 74.3 GJ of gas per year, or $ 743 USD of gas. We would save 413 $ per year by switching over.

The neighbours next door spent $ 17000 USD to install a multi-zone heat pump, which still doesn't exactly cover every room. It's a Samsung, so by the general sentiment about their appliances here, we'll assume it doesn't last longer than 15 years and needs to be replaced at a cost of 12000 $ USD down the line.

The hot water, low efficiency 80% boiler has lasted 35 years so far. Total cost of maintenance and repairs has been under $1500 USD. We expect it to last another 30 years easily because there is absolutely nothing special, fragile, or expensive in this system. Most of the spare parts can be found by walking down the alley and seeing which neighbour fell for the "replace your heating system" salesman tactics.

If we replaced it with a "high efficiency" condensing type, we would save at most 20% on our gas bill (143 USD a year). The cost to install will be easily $5000. As a reward for doing so, we will have to pay for maintenance every 5 years at $200, and the device will fail and need to be replaced for another $4000 after 15 years. This is a statistical and practical certainty because condensate is corrosive.

For the next 30 years, the old boiler we have will cost 23790 USD in total.

Upgrading to a high efficiency boiler will cost us $28032 USD in total, not including ANY breakdowns

Using a heat pump will cost $38900 USD in total, not including any maintenance, which you ABSOLUTELY need to do otherwise it smells and grows mould. (we do this maintenance ourselves but the design of the unit is ghastly, I curse the designer out loud every time I think of it, and this is a MAJOR pain to do.)

Based on this math, there is absolutely no reason we would ever consider making any of these changes. A plumber tried to suggest something like this and they seemed to agree.

With this said, I have a heat pump in my room, originally installed because I had too many computers and I needed air conditioning. We bought the absolute cheapest unit we could find at 700 USD and it has been wonderful. It has a capillary tube instead of an EXV because it's cheap, but it works "fine" down to -5 and it rarely goes under that here.

The greatest benefit of a heat pump has nothing to do with energy efficiency or savings. The greatest benefit is that every room can have their own heating and cooling controls that respond FAST. I turn it up and down all the time when I feel like it and it's wonderful.

abdullahkhalids• 3 years ago

Do your calculations include the changes in utility prices?

I don't know if this is the right place to look at, But over the last 30 years, in BC, the "Electric power selling price under 5000kw index" has gone from 56.8 to 120.9, about an increase of 110%.

[1] https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=181002...

vladgur2• 3 years ago

Is there a good calculator where I can enter my cost for units of electricity and gas and it will tell me how much operating a heat pump will save me over a gas furnace

timbit426• 3 years ago

To get a useful answer, you would have to put in more information. How many floors? How many sq ft per floor, what is the R value of your house? How cold can it get in the winter? How often is it that cold? Are you asking about air-to-air or ground-source heat pumps? The best thing to do is to get one or more local installers to give you an estimate.

billiam• 3 years ago

The other issue here in SF and near the coast is that for older, poorly insulated homes and those with high ceilings (mine are 12 feet), the real problem with an air heat pump is how slow it is to heat the volume. Unless you want to pay to keep your house warm 24-7 it will take an hour to warm up the whole house. I would love to kick my 10 year old forced air gas furnace to the curb, but I don't see how, even if I get solar. Contractors are charging a fortune for installing heat pumps these days too.

fragmede• 3 years ago

But, at 3x the efficiency of a traditional gas furnace, it may still be cheaper to heat the house all day, or have it start heating at 4:30 pm.

timbit426• 3 years ago

Heat pumps aren't meant to be turned on and off. In fact, they aren't meant to have the thermostat changed either, even at night. You set it to what you want and it keeps it there. Once it gets the temp where you set it, it doesn't use much electricity to keep it there unless it is very cold, like below freezing and especially below -20C.

Due to your high ceilings, it might be prudent to install ceiling fans to help circulate the heat, but I'm not a heating expert so I recommend asking one.

How a heat pump works

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