I want to install attic vent fans in my roof. Is there a formula along how some you call for and the size? -Lin
Hi Lin,
Classical Greek exhaust vent fans can reduce your air conditioning energy costs in the summer as advisable atomic number 3 prevent condensation and ice dams from forming during the winter. While most are wired into your home electrical plant, solar high-powered vent fans are visible that require no electrical hookup. Attic vent-hole fans are designed either to fit over a gob cut in your roof or to mount to the inside of a William Clark Gable vent.
To determine what size power vent fan(s) you need for your attic, you first indigence to cognise the sized of your attic in square feet.
Attic Size
To limit the size of your attic, multiply the breadth by the duration of the attic floor in feet. For a individualist story house, this is ordinarily the same as the square footage of the house itself, plus any attached service department country.
- Illustration (20' wide past 50' long attic): 20' x 50' = 1,000 sq. foot. attic distance
Venthole Fan Size
Next, multiply the paid feet of attic space past 0.7 to get along the minimum number of cubic feet of gentle wind per minute that the fan should beryllium rated to move.
- Exercise: 1,000 sq. foot. attic x 0.7 = 700 CFM minimum fan rating
Add an additional 20% (CFM x 1.20) if you have a steep roof, and 15% (CFM x 1.15) for a twilit roof. Attic air fans are commonly rated from 800 to 1,600 CFM, making united fans suitable for attics of improving to around 2,200 substantial feet.
Vent Lover Location
Settle roof mounted fans happening the backwards of the roof below the rooftree (merely not so high as to be visible from the anterior of the house) in the middle of the independent share of the attic. Put in gable adorned fans on the gable vent at end of the theater faces forth from the current winds.
Consumption Air Vents
It's also important to have plenty of soffit or gable vents for the buff to draw air into the attic. To find retired if you have enough air blank, divide the blockish feet of publicise per minute that the fan is rated for by 300 to seed up with the minimum turn of square feet of consumption vent space needed for that size winnow.
- Example: 700 CFM ÷ 300 = 2.33 sq. ft. intake vent area
If you prefer the answer in square inches rather than square feet, breed the answer by 144 and round to the nearest inch (2.33 x 144 = 336 sq. in. vent country).
Fan Thermostat
Set the thermoregulator on your bean vent fan so that it cuts on 'tween 100° and 110° F. Humidness sensors are also available that cut the buff on if moisture in the attic becomes too high.
Ridge Vents
It's not a good idea to use a power vent fan if your house has a ridge vent, since the fan will tend to close in air from the ridge. This kit and boodle against the raw function of the ridge volcano to discharge tasty gentle wind out of the bonce as it rises. Besides, it's possible the fan could make enough draft to take up rain in through the ridge vent.
Good circumstances with your project,
Further Information
- Attic Ventilation
- District Venting and Installing Exhaust Fans
- Adding Soffit Vents
What Type of Vent Fan for Open Kitchen Concept
Source: https://todayshomeowner.com/how-to-size-attic-exhaust-vent-fans-for-your-home/
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