[kevincox]

You can use a heat exchanger to get "fresher" air while keeping the heat/cool inside. Although many places don't have this in place. It is probably mostly due to lack of awareness or concern than any technical reason.

[endisneigh]

Cost

[switchbak]

Letting your warm air go directly outside also has a cost.

Getting poor air quality for decades also has a cost.

Typing more than a one word reply is pretty cheap though.

[endisneigh]

you're right. things have tradeoffs. the point is that most barely have central AC with vents, let alone an HRV.

[switchbak]

Most homes don't have HRVs not only due to cost, but because homes didn't used to be tight enough to require them. We also didn't understand how important fresh air is.

Many homes didn't have AC because a) it was expensive, and b) you used to not need it as much.

And plenty of people can afford these things, cost is not the only consideration nor some magic word to dismiss the tech generally.

[endisneigh]

No one is dismissing anything