Window condensation is coming

Q: How can I stop window condensation? Last winter was our first in a newly built house and there was lots of water rolling down the inside of our windows and freezing during cold temperatures. I’ve complained to the builder and want to take steps to prevent the problem this winter. What can I do?

A: Your builder isn't directly to blame for the moisture problems and there’s nothing wrong with your home. That said, the water forming on your windows will cause problems if it's allowed to persist. You need to do something. More frequent use of exhaust fans and a higher indoor air temperature are both good starts, but they’re often insufficient to solve problems as extreme as yours. For many new homes the only real solution to excessive window condensation is a heat recovery ventilator (HRV). It’s a ventilation appliance that brings a steady stream of fresh, dry wintertime air into your house, while exhausting stale, moist indoor air outside. And as it does this, it also recovers 80% to 90% of the heat energy from the outgoing air stream. HRVs cost about $2000 installed and can be used in homes with or without central heating ducts. An HRV is a guaranteed fix for your problem. I maintain that HRVs should be included in all new homes, but at the moment they’re not required by code.