Ventilation in new builds - are we overlooking something important?

I hear you. We went all-in on sealing up our last place, thinking it’d save a ton on bills. Instead, we got sweaty windows and a weird damp smell in the closets. Ended up cracking a window just to keep things from getting gross. Sometimes “old-fashioned” airflow just works better, even if it’s not as efficient on paper.

- Airtight homes are supposed to be more efficient, but only if you’ve got mechanical ventilation dialed in right (HRVs, ERVs, etc.).
- Just cracking a window can help, but you lose the energy savings you paid for with all that sealing work.
- “Old-fashioned” airflow works, but it’s not really predictable - depends on wind, weather, and how the house is built.
- I’ve seen some newer builds with properly balanced mechanical systems - no sweaty windows, no musty closets. It’s trickier to set up, but when it works, you get both fresh air and lower bills.
- Sometimes the issue is just not enough vents or poor placement. I had a job last month where the bathroom vent was basically useless, so moisture built up everywhere.
- Not saying old-school is always worse, but if you’re already investing in sealing everything up, might as well go all-in and get the right ventilation system too. Otherwise, it’s like wearing a raincoat with holes in it... kind of defeats the purpose.

Had a builder push the “airtight and efficient” line pretty hard when we built our place five years ago. Didn’t mention much about ventilation beyond “just open a window if it gets stuffy.” Well, first winter we had condensation dripping down the windows and a closet that started to smell like a swamp. Ended up retrofitting an HRV, which honestly wasn’t cheap or simple after the fact. I get the energy savings argument, but if you don’t get the ventilation right from the start, you’re just trading one problem for another.

Didn’t mention much about ventilation beyond “just open a window if it gets stuffy.”

Heard that one a few too many times. I once worked on a place where the attic was sealed up tighter than a drum, and the homeowners couldn’t figure out why their insulation was soggy and their roof deck looked like it had been left in a rainforest. All that “airtight” talk sounds good until you’re scraping black mold off plywood. If you’re building new, I’d say: plan for the vents first, then worry about the fancy windows. Otherwise you’re just asking for trouble (and expensive retrofits).

Yeah, I’ve seen that “just crack a window” advice backfire too. One job, the builder skipped proper soffit vents and the whole attic turned into a sauna - ice dams in winter, drippy insulation year-round. It’s wild how fast moisture sneaks up if you don’t plan for airflow. Fancy windows won’t save you from a soggy mess overhead.