How Many Attic Fans Do I Need

Note that these two feet would not need to be one large opening.

How many attic fans do i need. One static vent style is the turbine vent which uses wind to power its enclosed fan all it takes is a light breeze to rotate the blades and suck heat out of the attic view example on the home. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space. The amount of solar attic fans a home needs will ultimately depend on many factors. Your soffit ventilation actually needs to be considerably more than 336 net square inches to supply a 700 cfm fan system or the fan is going to pull the air it needs through unsealed holes and gaps in the attic floor from the conditioned living space.

To reduce that expense some homeowners buy an electric or solar attic ventilator. 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 dark roof. Tips for assessing your needs. All of that is in place.

So if your fan is rated at 1500 cfm you will need about two feet of totally open space in your attic. This is done because you need one square foot of ventilation area for every 750 cfm that your fan can push. Use the calculator below to find out how many exhaust and intake vents you will need on your house. I had my attic floor sealed and a good amount of blown in insulation.

When i last had a new roof installed a few years ago i calculated the soffit intake area i d need for the ridge vent specs. The moving air tries to cool down all the wood attic framing as without the fan the temperature. This fan moves 1 000 or more cubic feet of air per minute creating low pressure in your attic. Attic vent fans are commonly rated from 800 to 1 600 cfm making one fans suitable for attics of up to around 2 200 square feet.

Vaulted ceilings obstructions and the amount of existing ventilation from soffit vents ridge vents and gable vents should all be considered. Electric attic fans however often increase energy consumption and cancel out any savings unless the attic is not insulated at all. This will make determining the quantity type and placement of solar fans much easier and more effective. Now take that number and divide it by 750.

If you want your home air conditioner to cool you better then you might want one or two attic fans.