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Heat and moisture accumulate in the attic.
When unventilated, the attic of your home represents a huge volume of trapped air sitting on top of your home. In the summer, radiant energy from the sun's rays are absorbed through your roof and heat the attic of your home to as much as 30°F hotter than the outside air. Moisture from various sources also makes its way into the attic, creating a hot, humid environment that is positively hostile to the equipment and structural elements located in the attic.
Heat from the attic flows into your home.
Heat flows from a hotter object to a nearby cooler object. In the heat of summer, your attic can reach 130°F, while you are paying for air conditioning to keep your home around 75°F. This large temperature difference results in major heat flow from the attic into your home, causing your air conditioner to struggle to keep up and your utility bills to increase.
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Keep the heat out of the attic.
There are two ways to cool down the attic:
- installing Radiant Barrier, which prevents radiant heat from the hot roof from entering the attic,
- and installing Attic Fans, which forcefully circulate air between the attic and the outside air, keeping the attic temperature close to the outdoor temperature and reducing moisture buildup.
Passive ventilation is not enough.
Most homes come with some type of louver- or rotary-type vents, but these are unpowered and rely on convection effects to exchange the attic air with the outside air. The air flow rate with these types of vents is not nearly enough to keep with the radiant heat coming in during the summer. Powered fans force the hot, moist air out of the attic at a much higher rate. Available solar powered attic fans do so without any operating cost.
