Tips for increasing attic ventilation include installing soffit vents, adding rafter vents to prevent insulation blocking the vents and installing roof vents. Homeowners should avoid attic fan ventilators with blocked soffit vents, according to Energy Star.
Most building codes require 1 square foot of venting for each 150 square feet of attic space, according to the Family Handyman. Half of the venting needs to be located in the soffits with the other half high on the roof. Rectangular vents are an easy way to increase the soffit venting for homes that do not meet this requirement.
Covering soffit vents with insulation prevents them from doing their job, reports Energy Star. Rafter vents fit between the roof rafters to provide a tunnel that prevents insulation from blocking the vents. Once they are in place, it is possible to add any extra insulation needed to ensure the home insulation reaches the recommended R-value.
Adding vents high on the roof helps to provide a natural chimney effect to eliminate hot stale air from the attic without using electrical power. Installation about 15 inches below the roof peak is ideal, according to the Family Handyman.
While power vents increase attic ventilation, adding such vents with blocked soffit vents increases the cost of cooling a home, according to Energy Star. If the power ventilator cannot draw air through the soffit vents, it pulls cooled air from the home, increasing power consumption.