Attic Ventilation Fans: Cool, And Crucial, Equipment

Without attic ventilation fans, one area of your home is approximately 75 degrees hotter than the rest of the house all summer long. Separated from your living spaces only by a common ceiling, attic temperatures may soar to over 150 degrees on hot days in South Florida. This heat conducts down through the ceiling and seeps in through every crack and gap in the structure. Rooms beneath the attic sustain up to 10 degree temperature increases, increasing your home’s cooling load and raising your utility bill.

Attic ventilation fans boost the passive ventilation designed to circulate air through the attic. Cool air flows into the attic through soffit vents in the eaves. As the air warms, it rises to the top of the attic and flows out through vents at the gables and the ridge of the roof. Powered attic ventilation fans installed at the peak of the roof and activated by a thermal switch increase the natural circulation. This saves energy and prevents damage to the structure of the attic and roof from extreme heat.

Here’s some of the fine print about selecting an attic fan:

• The Home Ventilation Institute recommends an attic fan with sufficient capacity to turn over the entire air volume of the attic 10 times per hour in order to bring attic temperatures below 100 degrees.
• An attic fan rated at 850 cubic feet per minute (CFM) is sufficient to ventilate a 1,200-square-foot attic. A single attic fan with 1,650 CFM capacity, or two smaller models, is required to ventilate 3,200 square feet.
• Soffit vents should be large enough to accommodate the increased air intake of an attic fan. Total soffit ventilation should equal one square foot per 360 CFM of fan capacity.
• Typically, an attic fan will pay for itself in reduced energy costs in just two to three summers of use.

Serving Martin, St. Lucie, Indian River and Palm Beach counties since 1973, NisAir Air Conditioning & Heating is your family-owned source for interior home comfort. Call us for more information about the benefits of attic ventilation fans.