Because typically attic fans are so strong that not only do they take the hot air out of the attic but they reach down into your house and take the cool air out of the house as well.
Attic fan vs air conditioning.
Otherwise the fan will actually pull air conditioned air from the living area through cracks in the ceiling forcing the home s air conditioner to work harder.
A whole house fan moves air throughout the entire home including the living space and attic while an attic fan merely circulates air inside the attic.
Keep in mind that they re doing two separate things.
This prevents hot air from seeping into your home and driving up the temperature in the living space which reduces the load on your air conditioner.
In some instances a fan will suffice.
Using attic fans in cold climates.
The benefit from lowering temperatures in the attic and thus reducing heat gain from the attic into the house is.
Since gable attic fans remove the hottest air in the home your air conditioner will be more efficient and you may be able to run it less while still effectively cooling your home.
One to blow in the other to blow out.
Both types of attic fans are popular as solar powered equipment.
Gable fans operate as two separate units on opposite sides of the attic.
Another concern is that withinadequate ventilation the attic fan can createbackdrafting conditionswith combustion powered appliances such as gas stoves and gas water heaters.
Now if you did have central air conditioning i would tell you not to install an attic fan and here s why.
Compared to an air conditioning unit whole house fans are much less expensive to operate more environmentally friendly and more efficient at cooling.
Rooftop fans are installed right on top of the roof and perform two tasks at once.
An air conditioner while serving many of the same purposes is different than a whole house fan.
Energy usage of about 40 watts at medium speed is typical.
Running a fan is always a lot cheaper than running an air conditioner.
In others you ll need air.
How is an ac system different.
When set at low speed fans use between 15 and 30 watts and at high speed they consume between 50 and 100 watts.
In most parts of the country including colorado and during most parts of the year a whole house fan can adequately substitute for an a c system and provide a lovely living environment.
When used in conjunction with an air conditioner ceiling fans may allow you to set your thermostat at a higher temperature and still be comfortable thereby reducing your overall energy consumption.
Oh an attic fan will do that.
In general attic fans are not effective at reducing air conditioning costs.