We changed our roof and cut CO2 emissions

http://www.martindaniel.co/roof/index.html

by Lemaxoxo • 4 years ago

122 114 4 years ago

martindaniel.co

jopsen• 4 years ago

Insolation is an extremely effective way to save energy.

But with cold bridges and such it can be a little complicated to get right.

_Microft• 4 years ago

That's insulation but insolation can also help with saving energy ;)

codeduck• 4 years ago

I'm guessing `insolation` turns you into a clean energy source. Can't imagine it's good for the immediate surroundings though.

HPsquared• 4 years ago

If you have enough insulation, all you need is insolation.

nraynaud2• 4 years ago

Did I miss the amortization of the CO2 emitted during the change?

omgitsabird• 4 years ago

To preface, I am not trying to nitpick here. I am generally curious.

Is this a correct usage of amortization?

https://www.merriam-webster.com/dictionary/amortization

nraynaud2• 4 years ago

I don’t know, I’m not a native English speaker. I meant that: “to gradually reduce or write off the cost or value of (something, such as an asset)”

dotancohen4• 4 years ago

It is clear what the GP meant. What would be the correct word?

habibur• 4 years ago

1.5 tons in 6 months.

this period is important. otherwise number doesn't mean much to me.

ClumsyPilot2• 4 years ago

The annual carbon budget of each person is about 3 tons per person.

Thats the amount planet's biosphere can process divided by number of peoplle.

DoingIsLearning6• 4 years ago

annual carbon budget of each person is about 3 tons per person

To put that stat in perspective, the average carbon emmisions per person [0]:

Qatar is almost 40 tonnes pp

United States, Canada, Australia is about 15 tonnes pp

Switzerland, France, Italy, under 5 tonnes pp

South Sudan is about 0.13 tonnes.

It really puts in perspective how much wasteful carbon reduction and lifestyle changes are needed for us to have any reasonable expectation at curbing this.

Edit: added source

[0] https://ourworldindata.org/grapher/co-emissions-per-capita

sgt6• 4 years ago

They may be saving energy, but 17.2°C average temperature indoors is freezing.

jb1991• 4 years ago

No it’s not. That’s a very normal temperature for our bedroom in the winter time. It probably depends where you’re from, in colder climates people are used to it.

sgt6• 4 years ago

Yeah but this was the entire flat, right? A cold bedroom is nice, but not trying to type on a keyboard in 17C.

pw6hv• 4 years ago

Actually my experience is the opposite. In colder climates such as Russia, Finland I have seen room temperatures to be quite mild, above 20C for sure. However, in Italy in winter it is quite cold inside.

Needless to say that thermal insulation is awful in IT.

nemetroid2• 4 years ago

in colder climates people are used to it

It's the other way around. Indoor temperature varying with the outdoor temperature is one of those weird things you experience when going abroad from your colder climate, at least in Europe.

avgcorrection• 4 years ago

That could be the temperature of my bedroom. Which I only sleep in. I also bring a warm water bottle to bed every night.

I don’t know if I live in a cold climate but people will start to complain if the temperature goes below 21C indoors.

balfirevic3• 4 years ago

I only found out that you don't have to be freezing your ass of for the entire winter (and a big part of fall and spring) when I went to a university and moved from my coastal home town to the colder continental city. It's cold enough there that they can't pretend that "it's not cold" with a straight face.

cameronh902• 4 years ago

Average UK indoor temperature is about 17.5c-18c apparently so hardly freezing. A bit chillier than I like in my office.

Personally in winter I heat my house to 14c as a minimum, 20c in the living room and office. Reason being I only need warmth if I'm sat down and not moving, so any higher and I start to get too hot.

iso1631• 4 years ago

For the last 20 years "helpful" people have been saying "reduce your thermostat by 1 degree to save on your energy bills"

My temperature is now approaching absolute zero.

blunte• 4 years ago

I work in temps as low as 5 C and as high as 34 C in this old Dutch house attic. It's not at all pleasant, but there's no upgrading this rented place. It's not worth it for the owner as they will never recover their costs by increased rent.

So I wear 3-4 layers, including fingerless gloves and a hat. It looks ridiculous, but nobody sees me. And in summer, well... I don't wear much or anything. I at least put on a shirt for video calls :P.

Frankly, it sucks; and this is my last year here before I go nomad full-time.

eitland4• 4 years ago

I feel you.

Back in 2012 to 2015 I worked most of the time I think in the radio lab at the company I worked for at the time. Temperature was often above 30 degrees in the summer. I didn't think much of it back then, went into office, started working and forgot everything but after a while I realized I was drinking 1.5l water during the work day without needing to visit the restroom and I would be exhausted when I came home.

It was noisy and warm but almost no interruptions and still very nice compared to insulating an attic in in the summer (I've done that too so I know.)

(This winter I tried working from the garage in December but at below 0C it gets impractical even with really warm clothing.)

dorte• 4 years ago

I sit all day in front of the computer in something like that. Just use 60 s to put on two sweaters and woolen underwear and you will save money/the world. It's really weird to heat the whole house just to heat yourself.

avh02• 4 years ago

While I agree in the theoretical principle, I don't feel warm when everything I touch is cold... Floor, kitchen counters, desk, toilet, bed, it just never truly feels warm

Kosirich2• 4 years ago

The thing is 17.2 C is ok with good insulation and really cold with bad one. (so is 20 C for that matter)

balfirevic3• 4 years ago

In this context, do you mean 17.2C on the thermostat or as measured room air temperature?

empiricus3• 4 years ago

It would have been interesting to also estimate how much CO2 would be reduced if instead of a glass roof they used a normal properly insulated roof. So we can see what is the CO2 cost of a stylish glass roof.

Note: I suggest using underfloor heating, it should be more efficient with a glass roof, because there is less hot air to raise to the top of the house.

onion2k• 4 years ago

It would have been interesting to also estimate how much CO2 would be reduced if instead of a glass roof they used a normal properly insulated roof.

Buildings like this in Paris are often so tightly packed together that windows in walls barely provide any light. Replacing the roof with a more standard one would necessitate giving up any daylight and having lights on all the time.

cbg03• 4 years ago

Why would there be less hot air if you set the same indoor temperature? Hot air will rise no matter what.

empiricus3• 4 years ago

The interesting part of underfloor heating is that it is not the hot air that warms the room. It is the radiation from the floor. Smth like 10w/C/m2. And the heat profile in the room looks much better. For example https://www.researchgate.net/figure/An-example-of-vertical-t...

KaiserPro3• 4 years ago

One thing to point out is that yes, saving CO2 is grand, but this doesn't sell just how much more _comfortable_ decent insulation makes things.

I live in a '30s UK semi detached. It had an air brick , a blocked up fire place and blown double glazing in each room. (barring two that were replaced)

We had to re-render the place, as it was starting to fall off at the front, and the back was scarred from unfinished renovations.

We replaced the double glazing with triple (it was cheaper than double glazing at the time, so a no brainer. has a u-value of about 1.0)

We also put 90mm of external wall insulation round the outside as part of the re-render. This cost an extra £4k compared to just a normal re-render.

before the insulation, in summer the front room would reach 37 degrees C with the blinds down, and in winter with a 5kw wood burner and central heating on full we'd reach about 18 degrees c when outside was either windy or -3c

Now in summer the hottest we've had it is about 29, with the blinds open. In winter we reach 20 within 30 minutes of the heating coming on. ( no need for the wood burner)

dghughes2• 4 years ago

I wish I had done that to my father's home last year when he was alive. I didn't realize how much heat can come into a home from the attic. The joists act as a heat bridge radiating heat down from the ceiling. I plan on installing fibre wool in two layers one in joist cavities and one perpendicular over the exposed wood frame.

My parents also have a door to the attic for storage and heat leaks up through the un-insulated edge of the pull-down stairs door.

On YouTube Matt Risinger is a great resource for home repair and information. He tends to like expensive products but overall he explains main concepts well.

specialist• 4 years ago

Am a huge fan of Risinger.

Early on, Risinger did a bunch "building science" explainer videos. Challenging then conventional building practices. Like advanced framing (using 2x6 studs at 24" spacing). Like properly insulate attics to prevent condensation and heat loss (keep HVAC vents within the thermal envelope).

Those early explainers are the foundation (harhar) of subsequent product and project highlights. Alas, now they're hard to find (via YouTube's lame UX). Risinger should probably pin primers to the top of his playlist, linking into his archive.

https://www.youtube.com/c/MattRisinger/videos

throw0101a4• 4 years ago

We also put 90mm of external wall insulation round the outside as part of the re-render. This cost an extra £4k compared to just a normal re-render.

Having insulation on the outside of your structure, and especially outside of your air/vapour barrier, is ideally where you want it (behind whatever cladding you're using):

* https://www.buildingscience.com/documents/insights/bsi-001-t...

KaiserPro3• 4 years ago

100%

For us it stopped our moisture problem. We had mold growing on the walls, because all the moist air would hit the wall and dump out water (proper drops).

Now the walls are 10 degrees warmer, none of that condensation is built up.

there is also thermal mass and junk, but not having to wipe down the walls every night is a big big win

mannykannot4• 4 years ago

This is going off-topic somewhat, but I am thoroughly confused by the article you link to. The author insists we should put the rain control layer inside of the insulation, even on roofs.

He does not go into much detail on roofs, but in his wall examples, the outer cladding and the drained cavity behind it appear to be a de-facto rain control barrier outside of the insulation layer (which could be, he says, rock wool or glass fiber, which are surely a big problem if they get wet, right?) If this is so, then what does it mean to say the insulation is outside of the rain control barrier? Furthermore, if we combine these diagrams with the one showing a roof-wall junction, there does not seem to be any barrier against rainwater reaching the wall insulation that way, and I cannot see how this is not a problem.

clairity• 4 years ago

it seems these 'perfect' walls are really double walls, with an exterior wall and interior wall separated by a "control layer" that blocks air and moisture/vapor penetration, and reduces heat transfer.

the exterior wall features brick/stone cladding as a primary rain/UV barrier and thermal buffer, and a channel to wick away air, heat, and moisture on its interior, before hitting the "control layer".

the interior wall can be concrete block, steel frame, or wood frame, with only the latter insulated, and with a semi-permeable interior skin (gypsum board + latex paint).

both walls are designed to wick moisture away from the control layer to reduce mold and other problems.

the big downside to these perfect walls are that they're actually two walls, and as such, (roughly) twice the cost of regular stick-built walls, and they're twice as thick, which, given a fixed lot size, reduces interior square footage.

danShumway• 4 years ago

Specifically with insulation, have you had trouble with air exchange?

I keep hearing (to my naive/inexperienced/non-builder mind) contradictory advice about how insulated houses should be, and I've been trying to figure out how to square decreasing heating/cooling costs with keeping a house from feeling stuffy.

I guess for stuff like the triple glazing that's not really affecting air exchange in the first place, it's just preventing energy loss, since you're already not doing air exchange through your wall. And maybe getting better insulation in walls means you can crack open a window without it being as much of a problem?

liveoneggs• 4 years ago

As I understand it -- In a passive house you exchange air with an always-on air exchanger (HRV or ERV depending on your climate) which also has filters.

Mashimo• 4 years ago

I think houses often have air to air heat exchangers. They suck in air from the outside, and through the power of physics somehow warm it up or cool it down to match the room temperature.

Found this while searching: https://www.ag.ndsu.edu/publications/energy/air-to-air-heat-...

tenuousemphasis2• 4 years ago

Modern construction standards like Passive House call for an extremely well insulated and air tight building envelope. Because you're no longer losing conditioned air to drafts, they then use a system that constantly brings fresh air from outside, runs it through a heat exchanger to extract most of the heat (or cool, and in some cases moisture) from the conditioned air before it's exhausted. Generally you constantly pump fresh air into the living areas and bedrooms and exhaust air from the bathrooms and kitchen (places with lots of moisture and smells).

KaiserPro3• 4 years ago

Specifically with insulation, have you had trouble with air exchange?

I don't have empirical evidence, however I am pretty sure that we have reasonable air exchange. My evidence for this is threefold:

1) when we have used the log fire, it didn't kill us, or pull the door open.

2) there is still a slight draft,

3) we have a missing floorboard in the understairs cupboard

Whilst all of the air bricks in the rooms were covered, the suspended floor still has four bricks exposed. The triple glazing is sealed UPVC, however in the loft conversion we were forced to have trickle vents (I think thats overkill)

It doesn't ever feel stuffy, which is good. I do need to get a real CO2 monitor though.

One last bit of evidence is how quickly particulates from cooking disappear

sjsvsnd• 4 years ago

This is very important. But there’s a good solution (last paragraph).

Our old house, built in the 1920s had been basically sealed. Since it was only 1600 sqft and had no air ducts, the rooms were small and got terribly icky. Id crack the window open in the winter to get rid of the humidity (in PA, so hardly mild winter).

You have to realize that a lot of moisture from those those 8 tall glasses of water you’re supposed to drink leave your body as vapor. I think I’ve read half the water you expel is through your lungs [citation needed]?

If your house is sealed this water has no where to go. If there’s four of you it gets bad very quickly. This moisture eventually will escape through your drywall, into your insulation and finally through the cracks of tour siding; but that means materials that should be kept dry aren’t

Our new house is very drafty and I dont plan to fix that until I instal a heat exchanger. The air in the new house is much better, and despite being at least double in size our bills have only doubled (ie the added draftiness doesn’t seem to have had that big an effect)

The solution is a heat exchanger. This is a device that exhaust stale air and replacing it with fresh air while passing through a heat exchanger. You can have very large air flows with the outside almost free energetically.

kingnothing• 4 years ago

You can always consider installing an ERV to provide fresh air inside the house with minimal energy loss.

Kuinox• 4 years ago

nitpicking time :D

(assuming a 0.3g of CO2e per kWh

It's kg there, not g.

And this number is for the electricity, gas is 0.203 kg per kWh.

If you are indeed heating with electricity, in france the electricity CO2 is almost always below 100g of CO2e per kWh.

cbg03• 4 years ago

Is triple glazing still not a thing in most places? It's become pretty much standard here in Romania in everything but the cheapest windows.

teruakohatu• 4 years ago

In New Zealand it is available but I have never seen a house with it. Double glazing is the required minimum for new houses and has been for 20 years, but I would say at least half the country is single glazed.

sersi• 4 years ago

I wish! In Asia, single-pane/single-glazed is pretty much the standard. Even in 3600 usd/month apartments in Hong Kong, it's very unlikely you'll see double glazing.

It drives me up the wall, winters are not long and it doesn't get that cold but there's a few days a year when the weather drops to around 12 degrees celcius within my apartment (so 54 degrees Fahrenheit) and as someone from colder climes that's used to central heating, I'll say that I much prefer a cold winter with a warm home than a mild winter with a super cold home. I've seen the same when I lived in Japan...

Additionally due to the poor insulation, you get to hear the noise outside quite a bit which I personally hate.

CorrectHorseBat• 4 years ago

And it also helps with the heat in summer

toyg• 4 years ago

In UK double-glazing is basically everywhere, with triple typically replacing it as windows fail.

However, there is still a significant amount of single-glazed properties in poorer areas or in listed historical buildings.

lbriner3• 4 years ago

Yeah, Councils can be really bad at requiring people to either replace their old single-glazing with some exactly the same in double-glazed or keep the old inefficient windows. This is understandable for historical buildings but we experienced it with a box office building built in the 1970s, cost us another £11K to get cream coloured uPVC windows instead of white ones.

I think that might change as we go towards energy efficiency, we need to swing the needle back towards more efficiency = good.

bromley2• 4 years ago

Nice savings! Tho no ingenuity is needed to calculate them as there is actually an established process used in the energy saving business. It uses "degree days" that are derived from temperature measurements, rather than using temperature measurements directly.

Degree days work better in regression as, assuming the correct base temperature is chosen/calculated, heating degree days are directly proportional to heating energy consumption (including being zero when it is warm enough that no heating is needed) and cooling degree days are directly proportional to cooling energy consumption.

More info and data here: https://www.degreedays.net

including an article explaining the process typically used for before/after calculations:

https://www.degreedays.net/calculate-energy-savings

Disclaimer: I work for the company behind that site, and yeah I know it looks a bit dated :D

bromley2• 4 years ago

I'll just add a little more explanation here since our site goes pretty in depth and I imagine most here would only be interested in a brief overview:

So buildings have what is known as a heating base temperature, which is the outside temperature above which heating is not needed inside the building. This is not the thermostat temperature inside the building (say 20 C), it is actually lower because of various factors like people and electrical equipment generating "free heat" inside the building, and how well the building is insulated to retain that free heat.

The base temperature varies from building to building, but let's say, for example, a fairly-well-insulated home might have a heating base temperature of 14 C. If the temperature outside is 14 C or above, that building will stay perfectly warm inside on its own, without the heating system needing to come on.

But, if the outside temperature drops below 14 C the building will need some heating to keep it comfortable inside. How much heating it needs will depend on how much the temperature drops below 14 C, and for how long.

And this is what heating degree days quantify. Here is an example diagram that demonstrates quite nicely how they are calculated (using a base temperature of 14 C):

https://www.degreedays.net/images/heating-degree-days-calcul...

The neat thing is that the heating degree days for any period of time represent all the relevant temperature variations across that period of time, and assuming you used an appropriate base temperature, are proportional to the heating energy consumption over that period of time. So for example you can have just one figure that represents the heating degree days across an entire week/month/year, and that will encapsulate all the relevant temperature variations across that week/month/year.

If January had 200 heating degree days, and February had 300, you can expect the heating energy consumption of the building to be 50% greater in February than in January. (Assuming you have chosen the right base temperature for your building that is!)

Compare this with knowing that the average temperature across a week/month/year was 12 C. What does that tell you about how much heating was needed in that week/month/year? Not a lot, cos you have no idea how much it varied within that time. This is the case even within a single day, since the temperature can vary a lot within a day.

Hence why people in the energy-saving business would typically use degree days rather than temperature data :)

(That said, hourly temperature data or similar is good for more sophisticated building simulations. But those are a lot more involved. On the simpler end of the spectrum degree days are a much better choice.)

dghughes2• 4 years ago

One thing people are not so much aware about other than insulation is air sealing. A tiny gap that may seem like nothing is in fact very bad. Take windows notoriously bad for heat and air leaks. A small seam along a window that isn't locked (it should be) could be the equivalent of having a 1cm hole in the wall.

If insulated well and air sealed a home would lose very little energy. But also you'd need a good air handling system to move and refresh the air.

kleiba• 4 years ago

That's right. The other day I drove by a house that's currently undergoing renovation, but the guy who owns the house does everything himself in a jack-of-all-trades kind of manner. He had put on a nice thick layer of insulation on the outside, but the sheets/blocks were apparently too short in some parts or simply fitted poorly, and in other areas I saw that he had just used some left-over cut-offs of various shapes and sizes in what looked almost like a mosaic. To make everything stick and fit, tons of sprayfoam has been used in an attempt to fill the inevitable large gaps (1 inch) between the blocks.

I kinda feel sorry for the guy, investing all the hard work and having good intentions, but due to poor workman ship he cannot expect to get the insulating effects he's surely hoping for.

lbriner3• 4 years ago

But also you'd need a good air handling system to move and refresh the air.

And therein is the rub! Ventilation is critical in building design and many older houses cannot easily be retrofitted with a mechanical ventilation system, not to mention the costs.

Also, sealing air gaps is pretty much impossible in a house that wasn't built this way. I have been trying all kinds of things in my (30 year old) house to seal up gaps but there are spaces inside the floors to the outside through small mortar gaps, spaces behind electrical sockets, gaps in various parts of the floor and even around windows between the finishing.

I would personally like to see a more top-level view from governments. In the UK, for instance, they should be targetting the oldest housing stock and simply replacing it. I know this is hard because people own their freeholds but if we are serious and if someone would get a nice warm house in return for their old house then I think most people would be up for it.

tenuousemphasis2• 4 years ago

Have you heard of AeroBarrier[0]? It's an aerosolized silicon sealant that is sprayed throughout a home while a pressure door system is used to negatively pressurize a house. The silicon is sucked through all the tiny gaps and fills them. It's pretty crazy.

[0] https://aeroseal.com/aerobarrier/how-aerobarrier-works/

Glench• 4 years ago

This is great.

I'd also like to point out that with switching from gas to heat pump heating/cooling you'd probably save even more on your bills and have 0 on-site carbon emissions and likely 0 off-site emissions as your electricity starts coming from non-carbon sources. Heat pumps are around 3x more efficient than the most efficient gas heating because they're just moving heat around, not creating heat.

As Saul Griffith says[0], "You can't 'efficiency' your way to 0" (meaning 0 emissions, which is what we need).

Efficiency is a great win for our bills and cutting some emissions but even if every building made their current systems more efficient, we'd still be on track for over 1.5C of warming. What we need is transformation, and most of that to electric heating/cooling/transport/cooking. And we need it fast, all across the residential and commercial economies in the next 2 decades with more in the next decade. It's going to be a war-time-like effort. Thanks for getting it started!

[0] https://mitpress.mit.edu/books/electrify

robomartin• 4 years ago

Interesting.

It would have been nice to add a calculation of the energy required and CO2 produced to manufacture, transport and install that roof.

I feel this is an important metric that is generally ignored in these conversations. And yet, it is crucially important in order to determine the true outcome.

That said, I understand just how complex this input can be to obtain. You can’t reduce it to a number per window. That’s not how it works.

In order for someone to produce those ten (or whatever) windows somewhere in the order of twenty companies must exist and operate constantly. Aluminum mining and processing, steel production, extruders, paint/coatings, chemicals, oil/petroleum, fasteners, cardboard and foam packaging, forklifts, trucks, CNC machines, computers, etc.

The point is: These companies don’t exist just for the 42.5 minutes it took to assemble and pack the windows. In order to be able to buy ten windows, they have to exist whether or not someone is buying that model window or not. The energy required and CO2 produced comes from the combination of all of these factors. And, yes, this is hard to estimate. Yet the numbers are very far from zero.

It’s like saying you are going to go live in a tent on a small island to reduce CO2 emissions while ignoring the car ride, flight and ferry that get you there and the freighter that delivered your possessions.

We changed our roof and cut CO2 emissions

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