Do attic fans really cool down a house?

You will not notice the difference your self. But your AC will. It will take some of the strain off of it. When your attic is oven temp the heat is at your ceiling. If you have ceiling fans you push it around the room causing it to end up near your thermostat. Effect is your AC runs more. If you get the heat out of the attic, your AC will be able to shut off more often thereby reducing your cooling bills, and repair bills on the AC. Place a thermometer in your attic and read it on a hot day. The temps are usually around 130 degrees. Now turn on the attic fan and come back in about an hour. You will notice a change. It may not be 80 in the attic now, but it will for sure be cooler.

Attic Fan Home Depot

Home Depot Attic Fan

Ventilating an attic is a good thing to do and you will notice an improvement in how comfortable your house is. There are various ways to ventilate an attic, however, and using an attic fan isn't always the best way. You need to consider how it will relate to existing attic ventilation you have (if any). For example, if you already have soffit vents and a full length ridge vent, a fan might not provide any benefit.

If you do decide on a solar fan, here's how to install it, along with a video clip showing the process:

http://www.thisoldhouse.com/toh/video/0,,20047003,...

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RE:

Do attic fans really cool down a house?

Im thinking of buying the solar powered attic fan that Costco has to save on the AC but really need to know if they make a big difference (solar or electric ). It costs $369 so I need to know if it's worth the investmen. Thanks

$369 sounds like a lot for a simple attic fan - it doesn't need to be very powerfull... a cheap $30 at home depot or else where would do the same thing... The energy cost/saving of electric vs solar and your desire to be 'green' is something YOU need to work out :)

This is going to sound crazy, but I have (just for fun) gotten 20 solar yard lights off Craigslist.com for FREE... what happens is the batteries get a little corroded real quick so people 'think' they are dead... but all it takes is a brush to clean off the corrosion... the batteries and solar panels were fine... (the panels almost NEVER die...).

I hooked them in series on my shed roof and power a 12 volt battery and leave a light on (leds) all night long. You could do the same with an electric auto radiator fan - it may not charge enough... but it might get enough umphh to keep the attic cooler... neat project and VERY cheap :) BTW - the yard lamps batteries are 1.2 volts each - and the lamps typically have two or three in series so the output of one lamp is anywhere from 3-4 volts depending on sunlight. Hook the lamps circuitry in series and you end up with 3 volts X # of lamps... takes about 14+ volts to charge a car battery... if you want to get REALLY good service from it, you may need to invest $20 in a solar voltage regulator as well, but a cheap used car battery will last quite a while without 'burning out' by over/under charging... you may need to play with the number of panels to get the 'ideal' charge to keep the car battery at its best....

Oh yes! Attics get VERY hot in the summer. pulling in cooler air should make a big difference.