Ever wish you could just flip a switch and turn on a big whole house fan to cool your home? Well, it’s actually possible. As long as the outside temperature is less (or even the same) as the indoors, you have the ability to make your house way cooler. In fact, depending on the air temp outside, this approach is much more efficient (in terms of cost and time) than a home air conditioner. Most people don’t know how beneficial a whole house fan is. You probably have the concept in your head of this giant fan that helps pull outside air into your home. This is correct, but there is actually a lot more to it…and it’s all really good stuff. In fact, after reading this article, you’ll probably be sold on the idea. First things first though – let’s see what these benefits really are and if they make sense for you and your climate. Also, we’ll look at costs for fan systems as well as how to install a whole house fan.
What is a whole house fan?
Put simply, these are large fans mounted in the ceiling between your attic and top floor. When turned on, they suck outside air through open windows in your home up into the attic space, then out through attic vents. Think of a huge vacuum attached to your roof, sucking air right through your home. Fan assemblies usually consist of a fan motor with typical fan blades attached. The 
motor/fan can mount to framing members in the attic or directly on ceiling joists. Some models come with a 6 feet or so of duct work that connects the fan assembly to an opening in your house’s ceiling. This opening is anywhere from 14″ to 36″ big (circular or square-shaped), and is dressed with a vent cover. The fan motor is supplied electricity by plugging into a standard three-prong outlet installed nearby in the attic. Power and operation is controlled from below inside the house using a traditional light switch and/or timing device.
To install a whole house attic fan, you only need a few supplies such as a tape measure, drywall saw, screwdriver and electric drill/screwdriver. You can do most of the work yourself (a partner helps!), but probably want to use an electrician to bring power to the attic and install the whole house fan switch in your house.
Reasons you want a whole house fan
Obviously, using one of these fans will help to cool your house. When you think about the three ways in which it does this, you’ll begin to appreciate the abilities of these appliances. Beyond these, you’ll be happy to learn that you’re not just cooling air, but cleaning it. You’re also saving energy and money on your electric bill.
- First, a whole house fan creates a breeze as it pulls large amounts of air through your home. It doesn’t have to be that strong to instantly make you feel cooler. Like a ceiling fan blowing gently on you or being out on a hot day with a soft breeze, your entire home will have air movement dropping the perceived temperature 5-10 degrees.
- Second, whole house fans remove and replace all the hot, stale air in your home with fresh outdoor air. Even if the temperature outdoors is the same, the fact that you’ve removed the air contained inside will make a dramatic difference. It’s like getting into your car after it”s been sitting outside in the sun. You want to open the windows right away to get the stagnant air out.
- You might not have thought about this third reason, but it’s a pretty important one. Whole house fans, by their nature, also remove and replace all the air in your attic. If you’ve ever been in your attic on a sunny day, you know it can heat up to sauna like temperatures. Even though you may have insulation on your attic floor (you should!), hot air trapped in your attic acts like a thermal blanket, helping to keep your house warmer. By flushing this air completely out you’ll cool your house much faster; even if you use your air conditioner. Traditionally, when we turn on our A/C, we’re able to cool the inside of our house. But when this happens, the A/C shuts off. Then, the heated attic works to warm the house back up again, and the A/C flips back on. The cycle continues, often throughout the night as you sleep. Now, imagine if you removed that hot attic air first. A lot less A/C usage! By the way, an ordinary “attic fan” is nowhere near as efficient, because it isn’t pulling through the massive amounts of air a house fan generates from your open windows.
- When you remove, replace and continually move air through your house with a whole house fan you get the added benefit of supplying your home with cleaner air. You might think, ‘well, outside there is dirt, pollen and other pollutants’. This is true to some extent, but what can get stuck inside your house with closed doors and windows can be even worse.Many health organizations and government agencies believe that replenishing your home’s internal air with natural air from outside is the best way to have a healthy home environment. Getting sick and developing other ailments such as asthma are believed to be linked to poor indoor air quality. The Environmental Protection Agency (EPA) has concluded that most residential indoor air contains more pollution than outside air, even in metropolitan areas where this is smog. Not good when you consider how much time you spend inside.You may think that closing up your home and running your central air system will clean the air using an air filter. To a degree, your filter captures larger particles from dust, grease, etc. But what it doesn’t get are all the contaminants generated from every day living. Chemicals from beauty products, household cleaners, gas appliances and household furnishing (particle board in dressers or cabinets for example), permeate your home’s air. Also, germs from occupants, pets, etc. don’t get swept up from filters. They literally get circulated over and over because the same air is circulated over and over. The same is true with mold and mildew. A whole house fan gets rid of this air through ventilation and exhaustion.Think about this the next time you or a child gets sick. Wouldn’t it be nice to get rid of the contaminated air by installing a whole house fan to completed exhaust it out?
- You can’t talk about the benefits of a whole house fan without bringing up it’s huge cost savings. Sure, there is an initial investment of purchasing a fan and getting it installed in your attic. Fan’s can run hundreds of dollars, and if you really want to do it right, you will install multiple whole house fans to target specific rooms better. But then think about how you could cool your home down in as little as 15 minutes, operating a machine that costs a few pennies an hour to run. This, versus running an air conditioner that may take hours to cool your house down and costs dollars per hour to run. And after that, you haven’t even replaced the air in your home to get things clean and free of germs. Nor have you kicked out the hot attic air!
- One last note on cost savings is the fact that you can get rebates from your electric company by putting in a whole house fan. Contact your electricity provider and ask them what they can do. They probably already have a rebate program in place and a specific amount to give back to you for whole house fans.
How could you use a whole house fan?
If you think about a typical warm day, you and your family are probably out of the house most of the daylight hours at work, school, etc. When you come home, the air has been off and your house is really warm inside. If it’s 78 or more (or 74 or more if you’re more sensitive to heat), then you kick on your A/C. Sometimes, this can take until 8 or 9 o’clock at night to get your house down to an ideal temperature, i.e. in the low-70s. If you have an upstairs, it can be even longer. Well, by then the outside temp is probably at least that. (Of course, it depends on where you live. If you’re in Phoenix or Las Vegas in the summertime, it may not cool down enough until much later in the night!). If the outside temp reaches the high-70s, go ahead an turn on your whole house fans. Bring in the fresh air, and feel it flowing all around you. Even if it’s more humid, you’ll feel comfortable enough and will be saving quite a bit of money in the process.