> Typically only around 90% of the energy is recovered, even in ideal conditions. As opposed to the 0% of energy recovered when a house "breathes" (i.e., leaks

> Typically only around 90% of the energy is recovered, even in ideal conditions. As opposed to the 0% of energy recovered when a house "breathes" (i.e., leaks like a sieve) and lets out all the conditioned air? > That sounds good, but considering that for 'good air', you really want to be replacing the air fully every 10 minutes. [citation needed] ASHRAE 62.2 does not mandate nearly that much air exchange. A 2,000 sq. ft. (200 sq. m) home is about 20,000 cu. ft. of volume, and needs about 100 cfm of ventilation. And some folks (e.g., Lstiburek) think ASHRAE (at least the newer revisions) is too high: * https://www.energyvanguard.com/blog/lstiburek-has-new-ventilation-standard-resistance-may-not-be-futile/ https://www.energyvanguard.com/blog/lstiburek-has-new-ventil... * https://www.greenbuildingadvisor.com/article/how-much-fresh-air-does-your-home-need https://www.greenbuildingadvisor.com/article/how-much-fresh-...