Question: What are the most efficient and effective building practices to minimize window condensation?

Answer: Building in a desert would take care of the problem in a snap! But in less extreme climates, condensation can occur all too easily. The key to preventing condensation is to keep humidity levels inside the home at a normal level. Basically, condensation occurs when warm moist air meets a cold surface, for instance, when water droplets gather on a cold window inside a heated room.

To avoid condensation, make sure each room will receive proper airflow by correctly sizing the HVAC system according to the Air Conditioning Contractors of America’s (ACCA) Manual J calculations. Equipment that’s too small or too big won’t be able to maintain a proper level of humidity. BuildIQ University offers an online training course, Mechanicals: HVAC, that teaches how HVAC and air distribution systems function and how to check for a high-quality installation.

In addition to correctly sizing the HVAC system, use windows with a low U-value (below 0.35), and make sure walls are well-insulated and air sealed. Remember that building codes specify a minimum amount of insulation, not necessarily the amount that’s most efficient. The North American Insulation Manufacturers Association (NAIMA) provides more information and resources on its website about proper insulation.

It’s important to control excess moisture to prevent durability issues, as well as mold and mildew growth. Start by properly sizing the HVAC system, and back it up with efficient windows and insulation.

- Anthony Grisolia, IBACOS
Building Services Manager