A Dryer
Attic in Winter
A Cooler
Attic in Summer
Why Ventilate
in Winter?
Attic ventilation during winter conditions brings a different type of problem. During winter, the air inside the home is warmer and carries more water vapor than the colder, dryer air in the attic. Cooking, laundry, showers, humidifiers and other activities all contribute to this condition. There is a strong natural force, termed “vapor pressure”, that causes water vapor to migrate from high-humidity air or materials to low-humidity air. This migration of water vapor passes through ceilings, vapor barriors, insulation and wood. It moves into the attic space where it can readily condense on cooler structural members such as rafters, trusses, and especially the cold roof deck. Condensation moisture within an attic or ceiling space can dampen and compress insulation. Even small amounts of condensation can have a substantial effect in reducing the “R” value of the insulation, thus creating faster heat loss into the attic space. This will eventually lead to mold, mildew, rot, ice damming, etc. Having proper attic ventilation using the right attic vents will prevent all unwanted effects and keep your attic healthy.
Why Ventilate
in Summer?
Summer heat trapped in the attic creates a furnace effect, heating ceiling insulation which then radiates excess heat back downwards towards a home’s living space. This is why it is much warmer upstairs in the bedrooms than downstairs in the basement! Other problems that arise from an accumulation of hot air in the attic is the curling, or the bleeding of shingles, and the warping of the sheathing. This has a direct affect on the durability of the shingles and life of your roof while also sometimes not being covered by the manufactures or roofers warranty. Additionally, most homeowners don’t realize how attic heat buildup can increase cooling costs as their air conditioner will continuously run to compensate for the lack of proper ventilation in the attic. When attic ventilation is done right using active roof vents, heat buildup in the attic will be exhausted through proper air flow distribution coming from the soffit vents at the roof eaves all the way up to the Maximum vents. The result is an efficient roof ventilation system saving you energy costs and keeping your roof system healthy.
