> For an A+++ energy rated house, you can't have holes in walls where I live. That means you can't have cooker extractors that extract, you can only have them run the air through a filter.
It's possible to install dampers that are normally closed for airtightness, but open when the kitchen vent is activated (both on the exhaust, and makeup air, side of things):
Even the Passive House folks are fine with this arrangement (§3.4):
> When the exhaust air system is not operating the exhaust air and intake air vents should close airtight and should not cause any leakage volume flow. Furthermore, additional insulation will be advantageous at these locations.
In general theres two kinds of ways to meet code: by design or by test. They might be referring to a 'design' stipulation which wouldn't require a real test. If they choose to be tested instead, then the 'open when activated' would likely pass.
It's possible to install dampers that are normally closed for airtightness, but open when the kitchen vent is activated (both on the exhaust, and makeup air, side of things):
* https://www.greenbuildingadvisor.com/article/makeup-air-for-...
Even the Passive House folks are fine with this arrangement (§3.4):
> When the exhaust air system is not operating the exhaust air and intake air vents should close airtight and should not cause any leakage volume flow. Furthermore, additional insulation will be advantageous at these locations.
* https://passiv.de/downloads/05_extractor_hoods_guideline.pdf
So I'm not sure why your building codes mandate recirculation, since I'm guessing even they wouldn't be as "strict" as the PH folks.