They aren’t “airtight”, that would awful. They are well-insulated and designed to take advantage of passive solar heating and air exchange cooling. The way roofs and windows and orientation on the land is usually done for western homes is just terribly inefficient for capturing and releasing heat in the right ways. Just some thick walls, a bank of windows facing the sunrise ,and some proper roof vents that can be opened when it’s hot is all most passive houses really are.
They literally need to meet airtightness requirements to meet the Passive House standard. It’s tested with a blower door test to check the air exchange rate at a prescribed negative pressure. You may be referring to a loose definition of passive house, instead of the standard, though. Airtightness is not “awful” as you suggested - mechanical ventilation provides fresh air
Yes, they certainly have to meet requirements for air exchange. And if you define “airtightness” as that, then yes, the ones that met that definition met that definition. What they are not is the common definition of airtightness, as in a sealed glass jar, steel can, scuba tank, or submarine, which if you look at the comments here was what was confusing a lot of people. I don’t think anyone was contending that there aren’t tests that these houses have to pass, just that the word airtightness, as understood by laypeople, isn’t an accurate term to describe these homes.
Pfft you’ll never get accepted into journalism school with that attitude
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Has to be some kind of air exchanger
Sounds more dangerous than it’s worth.
Considering the number of people who have lived safely like this for years, and that some places (Massachusetts, USA) require it for apartment buildings/multi family units, makes me think it’s pretty well understood
Here is a schematic I found on the Swedish version of this article: https://upload.wikimedia.org/wikipedia/commons/0/00/Passive_House_scheme_1_multilingual.svg
I suspect not all passive houses are built in this except way though.
The WSJ article has a diagram explaining the air stuff
I live and own a passive house: Feel free to ask questions :)
Can you address any of the intuitive concerns around the air freshness and getting enough O2 and removing enough CO2 ?
How much is the air exchange process a complex active process that you need to monitor and maintain, or is it pretty basic and “just works”?
I would say “Pretty basic just works” it was adjusted during construction of the house and as long as you don’t do any fundamental changes to ventilation system there is no need to readjust.
Do you find yourself having to think about “optimal use” of the house? Or can you just live your life as you would have prior to ownership and reap the benefits of the engineering?
Most of the time I don’t think about it at all. There is have a central ventilation system with a heat exchanger. So I don’t even have to think about opening the windows for fresh air.
As a firefighter, Airtight sounds like a bomb if there’s ever a fire.
If there is a fire in in a air tight room and you close the door and stop the ventilation, wouldn’t the fire die out because of the lack of oxygen?
In an airtight room when there is a fire it consumes the oxygen and becomes ventilation controlled the room gets hotter and hotter and the combustible solids in the room continue to pyrolyze into flammable gasses but can’t burn because there is no oxygen. Then a firefighter opens the door…
There’s actually a vacuum in the room, it sucks fresh air in and all those flammable gasses and smoke ignite and explode.
It’s called a backdraft. It only happens when there is a tightly sealed home/room.
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Do the windows not open? Sounds like a good candidate for “sick building syndrome”.
According to the article the windows do open.
And of course they do. The building is designed to be well insulated, not to make you comfortable.
If the owner wants to let air in or out, of course they should be allowed to do that.
You never know. A lot of modern buildings (at least in the US) do not have windows that open. It’s a pet peeve of mine. Modern public school buildings are particularly poorly designed in this regard.
I recommend the Livable Low-carbon City podcast for information about building techniques like that.
