My issue with that is that in the summer, ventilation is ~impossible. It's 110 degrees out there, reasonable ventilation would mean either burning out my A/C or living with temps that are far too high.
I also couldn't spend thousands on an energy recovery ventilator (ERV) installation because I've been living in rental properties.
My solution was to buy an ERV for ~$500 and rig it up to an open window: https://gen.co/air
I've since moved into a condo with a bedroom with no windows and french glass doors so I installed a cat door and mounted the ERV vents to that.
I think there's a lot of money here for someone to build an ERV designed to be window mounted.
I rent right now, which means I doubt I can, but hoping to buy soonish.
Sounds like something that would be worth it, I spend almost all of my time indoors and we have pets pumping out co2 as well.
TTBOMK, there is nowhere in the US that an HRV or ERV is required by code [1], regardless of the price range. There are a lot of very expensive homes built with no thought to indoor air quality.
In many places in the US, due to higher air-tightness requirements, mechanical ventilation is required, but that can be as minimal as having bath fans and a kitchen extractor fan.
1. Ontario CA requires them on new builds https://www.huskyair.com/blog/newsflash-ontario-is-making-hr.... Maybe Germany also?
In the winter the situation is _much_ better, but probably 4 months out of the year, the outdoors are unlivable.
https://www.metoffice.gov.uk/about-us/press-office/news/weat...