101–110 of 133 posts
I bought a CO2 monitor. What a shock it was to see my office go over 1000ppm. I had no idea. Now I crack the window, and tweak that till the CO2 stays below 600 or thereabouts.
I bought a CO2 monitor. What a shock it was to see my office go over 1000ppm. I had no idea. Now I crack the window, and tweak that till the CO2 stays below 600 or thereabouts.
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Aren’t there heat exchanging ventillation systems that do this (maybe even better) without wasting a ton of energy?
We had a good one like that in our previous apartment. They consist of a large cylindrical metal "heat sink" where cold air coming in goes through the bottom half, warm air going out leaves through the top half, and the entire thing rotates at ~ 5 RPM. Not any more noisy than regular kitchen ventilation. But they need to be big, ours was the size of a small dishwasher and that was adequate for a 75 square meter apart…
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This sounds like teflon, approved because it is organically safe until it reaches a certain temp, even for a second, then it releases toxic gas, and becomss permanatly harmful to cook on. The approval logic was, people will: - always be very careful cooking, and never ever let the heat get too high - people will learn about teflon, and keep watch - people care Meanwhile, stories abound of people's birds dying from to…
>and becomss permanatly harmful to cook on. Source?
Grab a pan and wipe a tissue around the inside a few times... See the dirt that comes off... That's probably carbon and teflon deposits.
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>and becomss permanatly harmful to cook on. Source?
Burnt teflon flakes off into food. Grab a pan and wipe a tissue around the inside a few times... See the dirt that comes off... That's probably carbon and teflon deposits.
[1] https://en.wikipedia.org/wiki/Polytetrafluoroethylene#Ecotox...
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Venting the roof is standard in new construction, to protect the roof structure from moisture and excessive heat. They did the fiberboard chute so they could densely pack blown-in cellulose. Otherwise the insulation wouldn't have a good surface to push against (you don't want the insulation to touch the roof sheathing). On typical homes with blown-in ceiling insulation the insulators will staple cardboard against the…
Thanks for the details. Do you know why this isn't done for walls as well? It seems like the cellulose is packed directly against both the interior and exterior surfaces of the walls. Is it simply that hot air rises, and so it's needed more for the roof?
Part of the issue is that, yes, hot air rises, so a lot more moisture will find its way to the roof than to the walls.
Part of the issue is that roofs are (traditionally) sealed much more thoroughly than walls (because rain falls on roofs), so the moisture has a harder time getting out. The ventilation channels provide an egress for the moisture below the sealed roof surface.
A big part of the issue, at least in many climates, is snowfall. If it's cold outside and warm inside the house, any snow accumulated on the roof is melted from beneath and not from above. As the slush and water try to run down the roof under the unmelted snow, ice dams can form that prevent effective drainage; water pools and leaks down through the roof. A ventilation channel under the roof surface keeps the surface at or near outdoor temperatures, so the heat of the house doesn't melt the snow from beneath.
The main reason to make a building airtight is for energy efficiency. But it's pointless to go to such lengths for airtightness if you have massive thermal bridges in the walls and roof in so many places. If you want to be really efficient, the insulation should be constant thickness with no nails or screws poking into it, and certainly no bits of wood across it. Since the insulation has no mechanical strength, that…
I disagree. Airtightness is far more important than insulation. Insulation is worthless if air currents can simply carry the heat and bypass the insulation. And unless you're building an ICF house, some minor thermal bridging is unavoidable. But it does not matter because you can just insulate more somewhere else to make up for it. Exterior foamboard insulation around the entirety of the house is already quite common…
Using that calc - with typical R-Values for an old building of 1,000sq ft + ACH50 of 10 (converted to 0.5 for this since ACH50 values are at pressure) with a 0º outdoor temp and a 70º inside temp, the heating load would be 50k BTU. Doubling the insulation on the walls, doubling the R-Value of the windows, and doubling the roof insulation has the same impact as bringing the leakiness to an ACH50 of 3. One of those can be done with a few tubes of caulk, a few rolls of weather stripping, and some cans of spray foam. The other involves removing siding/drywall/roof material.
Everyone in building science will tell you that the "best dollars" on saving heating/cooling costs are spent in making your home tighter.
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Opening a window in winter in Wisconsin is very much not free... It's a classic OPEX vs. CAPEX tradeoff, plus the climate impact (of course building the ventilation system has a climate impact too, so there is a tradeoff there as well).
The one winter I lived in MN I had to open my windows or else the central heating in my apartment would have baked me alive.
https://www.bloomberg.com/news/articles/2020-08-05/the-curio...
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Opening a window is free, and not everyone has the freedom to modify their living arrangements(rented houses etc)
Opening a window in winter in Wisconsin is very much not free... It's a classic OPEX vs. CAPEX tradeoff, plus the climate impact (of course building the ventilation system has a climate impact too, so there is a tradeoff there as well).
How well do these operate if the electricity fails? If it’s airtight wouldn’t you eventually run out of oxygen?
Even if you're relatively reclusive, assuming you go outside once a day to get the mail... you'll be fine.