Cold Climate Attic Venting

Unventing roof assemblies in most cold climates decreases the heating load by about 10.

Cold climate attic venting. In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof membranes. In hot climates ventilation is just as important for the opposite reason. Keeping the attic space cool. A whole house fan is a fan that exhausts air from the home into the attic and out the attic vents.

Use rigid metal ducting aluminum or galvanized steel with lengthwise seams facing up and joints sealed with foil tape or duct mastic or rigid plastic pipe. In cold climates this is an advantage. Our field measurements and computer modeling show that without attic venting the temperature of the underside of the roof sheathing increases by 10 f 20 f. In cold climates attic ventilation is necessary for maintaining a warmer roof temperature which is essential for venting condensation and preventing ice dams.