Most people avoid the attic in summer and for good reason: Without an attic fan, attic temperatures can exceed 150 degrees during the hottest months in North Texas.
Living with a blast furnace a few feet over your head poses certain drawbacks. First, heat energy conducted down through your ceiling goes head-to-head with your air conditioner’s cooling capacity. Temperatures in living spaces below the attic can rise 10 degrees from conducted heat, escalating your utility costs. Second, wooden structural members in the attic may warp from the heat and humidity, and roof sheathing can buckle, dislodging shingles on the outside and causing leaks.
Passive ventilation designed into your home circulates attic air utilizing the “chimney effect.” Hot air rising out of gable vents at the peak of the roof creates a zone of lower air pressure in the attic, drawing outdoor air in through soffit vents down below the eaves. This continuous upward flow exhausts a limited amount of heat from the attic. A powered attic fan mounted on the roof boosts passive circulation.
Here’s how it works:
- By moving up to 1,650 cubic feet per minute (CFM), a powered fan will ventilate an attic up to 3,200 square feet. A smaller 850 CFM model handles attics up to 1,200 square feet.
- An attic fan can turn over the entire volume of attic air 10 times per hour, lowering temperatures as much as 50 degrees. This reduces the cooling load on your home, saves energy and protects the structure from heat damage.
- A thermal switch runs the fan at a preset temperature. This allows operation during summer heat only, decreasing winter circulation when attic heat helps warm the home.
- Reduced energy costs resulting from enhanced ventilation will usually pay for the fan in three years.
- Installing a solar-powered attic fan saves even more by utilizing the free energy of the sun. A 20-watt solar fan will ventilate a 1,600 square foot attic.
Since 1955, AirRite Air Conditioning has made the interior comfort of Ft. Worth/Arlington homeowners our business. Contact us for more details on stay-cool solutions like attic fans.
Our goal is to help educate our customers in the Fort Worth and Arlington, Texas area about energy and home comfort issues (specific to HVAC systems). For more information about attic fans and other HVAC topics, download our free Home Comfort Resource guide.
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