You know how when you’re standing outside on a cold winters’ day and you feel the cold wind against your skin? The cold temperature outside is a lot colder when it’s actually blowing against your skin then when the wind is at a standstill.

That is the principle behind whole house fans. Whole house fans are cheap to install, cheaper to operate, and can save you a ton of money on your energy bills. However, you need to be prepared before you attempt to have one installed.

Whole house fans were popular 100 years ago. Now, they’re making a comeback.

How It Works

Here’s how it works. These gigantic-sized fans work to circulate the air in your entire home – much as what happens when moving air touches your skin. In the summer, it is a welcome notion. It may be early in the year, but now is the time to start thinking about how you’re going to cool your home during the hot summer months. When this hot summer months get here, you are not going to use a whole house fan if you don’t already have one. You’re going to use whatever method is available to you. Therefore, now is the time to start thinking about how to save money in a few months when it does get hot.

The system pulls fresh air in from the outside where it is pushed throughout the rest of your home. As the name implies, it is a fan – not a cooling system by itself. It is meant and designed to work in conjunction with your central air conditioning system. However, except in sweltering climates, the two should not be on at the exact same time. That would actually be counterproductive as the whole house fan would push the cold air out of your home.

You’ll actually get the best use out of your whole house fan if you have it running when the air outside is cooler than the air inside it. Otherwise, you’re merely pushing the hot air from outside through your home. It is usually best run early in the morning, overnight, or simply on days when it’s just not as hot.

When a fan displaces air, it is measured in cubic feet per minute, or CFM. You can find this rating on vacuums, blowers and yes, whole house fans.

The higher the CFM, the faster it will displace air.

The Installation Process

Whole house fans are typically installed in the attic. That means that you need to have a lot more ventilation in your attic and you currently have. Attics can typically reach over 150°F in the summer. Plus, you don’t want your whole house fan to circulate gasses that may be harmful, such as carbon monoxide. Monoxide is a gas byproduct that is dangerous to your health, odorless and is created when gas or oil catches fire. This is how water heaters, furnaces, and even some stoves turn on. Don’t worry – as long as you’re not right down there by the pilot lights smelling the fumes, you’ll be OK.

As you will want to increase the ventilation your house gets, you also want to install ways to protect your home during the winter when you don’t want your house to be releasing heat. Install louvers that are programmed to close when the unit is off in the attic.

Your installer should be installing a hardwired timer switch so that you can program that the whole house fan to turn off by itself.

Whole house fan installation will set you back between $450-$600. Compare that to a $2000-$3000 air conditioning installation. Not only is it cheaper to install, cheaper to run, but will also make your air conditioner last longer and not have to work as hard. It cost between $0.01 and $0.05 per hour to run a whole house fan. It costs between $.20 and $.30 per hour to run your air conditioner.

Troubleshooting Potential Issues

Some things can go wrong when you’re running a whole house fan. Here is a quick rundown.

The suction effect that a whole house fan creates is very powerful. Make sure that your windows are open when it is on. This can prevent pressure and damage from things like a bedroom door randomly slamming shut.

Make sure your whole house fan is installed by a professional. This can eliminate the problem of noise and vibration. This is still a fan.

Whole house fans do not alleviate allergens. On days when pollen or cedar counts are high, it might be better for you to run your air conditioner instead. Otherwise, whole house fans can exacerbate allergy issues.

Whole house fans do not do anything to alleviate humidity. On particularly humid days, you may be better served by running your air conditioner instead.