Condensation on My Windows!

……with the recent cold snap, winter came in with a veritable ROAR! We thought we’d share some of our recent observations in dealing with condensation on windows and pass along some simple tips. As we build custom homes in Oakville, the information refers to the Oakville area known as climate zone 5 but the principles apply equally to any area.

With overnight temperatures in the -20c range, as we’ve seen recently, windows cool down and present a surface for moisture laden air to condense on. Much like a pop can sweating on a summer’s day, cold windows can cool the room air that touches it, down to such an extent that the moisture condenses out of the air and water builds up on your windows and window sills causing a mess and sometimes damaging interior paint work.

tip#1 check that your humidifier is set to the levels recommended for the outdoor temperatures ( these are usually printed on your humidifier). This may need tweaking but a very slight “halo” on the windows in the morning indicates the setting is about right.

tip#2 if you have one, set your HRV to run to bring down the humidity close to where your humidifier is set ( within about 10%)

HRV control

tip#3 curtains and blinds can block the flow of air from heating grilles, so if you have curtains closed at night you may need to decrease humidity levels to prevent condensation

tip#4 in newer houses (built within the last year or so) there is typically plenty of ambient moisture from the building drying process so the challenge will be to lower humidity levels to stop condensation build up ( see tip #2)

tip#5 further, with newer houses the building envelope is tighter than older homes, so depending on occupant use … washing, showering , cooking , laundry etc. the challenge may be to keep humidity levels as low as practical.

Higher performance glass for better insulation and condensation resistance

tip#6 if you have high performance windows you may be able to enjoy the benefits of higher humidity levels. Higher humidity levels between 35-50%  have been shown to have health benefits. on the other hand Low humidity levels have been shown to exacerbate the inevitable winter  coughs and colds