What causes condensation on windows and doors?

ALL windows, even the most energy-efficient, will experience condensation if the conditions are just right. For instance, if the indoor air has enough moisture, and if the window glass is cool enough (which depends on the outdoor temperature and the makeup and quality of the window). Some experts suggest this problem is seasonal. They may be correct. It’s not uncommon for windows to condensate during the change-of-season from summer to winter. As we keep our windows and doors closed due to the dropping temperatures outdoors, we are trapping all the moisture that the house has retained during the warmer seasons. It really is entirely possible that this problem will correct itself as the air becomes drier and winter sets in. But if you could lower your indoor relative humidity to 30%-35%, that would really help as well.

Try these tips to lower humidity in your home:

1. Turn down or stop using humidifiers.
2. Use range and bathroom exhaust fans while cooking and bathing, or open a window for a few minutes to bring in cool, dry air.
3. Cook with pans covered. (This also saves on utility bills.)
4. Take shorter showers with cooler water.
5. Vent clothes dryers to the outside.
6. In tightly insulated homes, consider installing an air-to-air heat exchanger.
7. In summer, use a dehumidifier.

Please visit the Understanding Condensation section of our site to learn more.