I think the Passiv Haus standard of 0.6 air changes per hour at 50 pascals is kinda nuts, and likely not worth it. The more relaxed "Pretty Good House" goal of

I think the Passiv Haus standard of 0.6 air changes per hour at 50 pascals is kinda nuts, and likely not worth it. The more relaxed "Pretty Good House" goal of 2 ACH is still pretty tight and requires ventilation, but is a bit more forgiving and acknowledges that a moderate amount of electricity for HVAC isn't so hard to come by. The catastrophe with older houses in the Midwest (where I'm from) is that they'll each put out a dozen or more tons of CO2 each winter due to fossil fuel heating. Regardless, the point is that even if you don't have one of these super-airtight houses, you can still install an HRV/ERV for not a ton of money. I'm considering one for my vacation cabin where the primary heat is a wood stove.