How well do these operate if the electricity fails? If it’s airtight wouldn’t you eventually run out of oxygen?
You can open the door or window.
assuming you wake up in time :-P
Detailed Assemblies for an Airtight Small Home
31–40 of 133 posts
Re: Detailed Assemblies for an Airtight Small Home
#32Re: Detailed Assemblies for an Airtight Small Home
#33Earlier quoted context omitted.
> "The unit has produced a public awareness film urging people to ventilate their homes properly by ‘keeping vents or windows open when cooking, showering and cleaning..." Why showering?
If you have an exhaust fan on to remove shower steam, the air needs to come from somewhere. You don’t want it getting sucked in through the walls (bad air quality). Better to open a window.
No. You need a fan+filter to exchange the air.
Re: Detailed Assemblies for an Airtight Small Home
#34Air tight homes and health problems. https://www.cibsejournal.com/news/airtight-new-homes-creatin...
It probably would make sense to have controlled and well-managed ventilation in airtight houses. It'd still be more energy efficient to heat and cool at a particular ventilation point rather than have what traditional houses have... a lot of leakage everywhere.
"makes more sense"? In Europe it's required by law.
Re: Detailed Assemblies for an Airtight Small Home
#35I'm curious about the "vent chute": the asphalt-coated fiberboard above the ceiling insulation, but set below the roof sheathing. It creates a cavity beneath the roof that is vented through the eaves. Anyone know why this is done?
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 lower few feet of roof framing, creating a similar vent space from eave to ridge.
This home's ceiling R-value of 82 is about 2.5 times standard.
Re: Detailed Assemblies for an Airtight Small Home
#36We did something similar recently. This looks like standard, low cost modern construction to me. If you’re in a warmish climate (like the SF bay area), you probably don’t want to insulate the concrete slab. You get lots of passive heating of the slab in winter already, and having the ground suck that heat out is a win almost year round. South facing windows can be designed with an eave, etc to lower passive heating i…
I build homes. This isn't standard in the US. I don't know how much cost it added -- probably not a lot. 10-20% I'm guessing. But, it's not low-cost.
Re: Detailed Assemblies for an Airtight Small Home
#37That's pretty much how a modern Danish mass-produced house is built, modulus some form language details.
Re: Detailed Assemblies for an Airtight Small Home
#38It seems like this could use some testing. How do we know that this really works even in one home? There should be some sensors and metrics to show how well variations work so that the design can be robustly optimized.
Good point, it seems from my perspective the industry is focused on blower-door tests and air exchange, where it's then kind of assumed that "you're done". I don't think there's real incentive at this point for residential building intelligence. We might have to wait for the 2nd (3rd?) wave of smart home tech to make it happen.
Re: Detailed Assemblies for an Airtight Small Home
#39Air tight homes and health problems. https://www.cibsejournal.com/news/airtight-new-homes-creatin...
Typically with passive houses/"pretty good" houses that have low inherent ACH they then have HRV/ERVs installed for mechanical ventilation, to provide good air quality. It's possible for such a building to have better air quality than normal construction. At the same time, the theory isn't always embodied correctly. The ventilation design may be poor or make wrong assumptions (like requiring bedroom doors to be open)…
Yes, I'm in exactly the same boat (although my house is even older - almost 70 years old).
I hope to gradually replace the leaky windows and external doors (would love to put in double-insulated windows), maybe staple air barrier membrane under the floorboards after insulating under them to reduce leakyness there (I already have good insulation in the ceiling). But first I want an ERV just to increase general air quality.
Re: Detailed Assemblies for an Airtight Small Home
#40It's interesting to me that hacker news likes building-related content so much, which happens to be my education other than... well, computers.
Air tightness is a critical step forward. I'm glad we are talking about it. Thinking more holistically, I would not go with the double-stud wall. You get lots of thermal bridging, and when it gets cold, your outer studs freeze. I know it's considered a straightforward system, but venturing out of one's comfort zone to do an exterior insulated system has enormous durability and performance benefits. Let's build our homes for centuries, not decades, folks!