for Cold Climate Housing and much more

Last Updated: , Created: Thursday, November 22nd, 2001

Should I install a turbine vent on my roof?

Vent yes, turbine no. A vent on the top of the roof is designed to let hot moist air out of the attic. It is critically important that air can get into the attic as low down as possible, ideally up through the soffits. This air then feeds up and out the roof top vents. When there are little or no vents low down, the higher roof vents tend to draw even more warm moist air into the attic from cracks in the ceiling, and when it is cold up there, that turns to frost, sometimes lots of frost.

Also, roof vents that are constantly covered in snow are not much use. So we want our vents to stand up high of the snow. The turbine does that, but there are serious problems with turbines in a cold climate. First of all, they don't do any more or any less good than passive vents when there is no wind. When the wind does blow they do in fact draw more air out of the attic. But when the wind blows, passive vents draw more air out of the attic than is needed anyway -- hence turbines work best when you don't need them. On a calm day when a bit of extra ventilation might be useful, they don't draw. Secondly they will all eventually get noisy and drive you and your neighbours crazy. If it completely freezes up, it will drive snow right into the attic like a scoop.

The MaxiVent shown in the graphics was invented in Quebec as a snow country roof vent. It stands up above the snow and has special baffles that prevent blowing snow from entering the attic. They draw well but not excessively and they don't move, or make any noise. Maxivent even makes one with a round base to allow you to simply pop off your turbine and replace it with a square copula. This is one ventilation company that is doing things right for our type of winter climate. They are made in Quebec and are slowly becoming available across the country.

Keywords: Attic, Roof, Ventilation

Article 1497