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Whole House Fans for Energy Efficiency

Whole house fans are gaining popularity in the United States. According to the Department of Energy, these appliances can be used in place of air conditioners, allowing you to cool your home using much less energy.

But how much can you save by installing a whole house fan?

While measuring the exact number is tricky, there are some resources you can use to get a clear picture of the potential energy savings.

Home energy efficiency

Understanding the Role of Whole House Fans

Before we can discuss the energy efficiency of a whole-house fan, it helps to understand these appliances and their roles in home comfort. A whole house fan is a product that is used to cool a house through natural air, which is brought in from the outside through vents and windows. In most cases, this means running the whole house fan in the evening, although the fans can be run during the day when weather is cool. And it always means turning the fan off and running the air conditioner when outside temperatures are unbearably high.

Since they create circulation, whole house fans can also help prevent mold.

The whole house fan is placed in the ceiling of a home between the attic and the living space. A hole will need to be cut in the ceiling and the fan will need to be properly installed. Proper attic ventilation will also need to be created if it doesn't already exist in the home. Once it is in place, the whole house fan pulls air from the living space into the attic where it is pushed out through the attic vents. To ensure smooth operation, there also needs to be ventilation from the living space, which usually comes in the form of open windows.

Essentially, whole house fans, which are different from attic fans, create a ventilation of air from the outside, through the windows, through the ceiling via the fan, into the attic, the back outside through the attic vents. This air circulation creates a cooling breeze and helps to regulate the interior temperature. If it is hot outside, the whole house fan is no longer effective because the unit simply pulls in hot air. In contrast, an attic cooling fan resides in the attic and is used to push hot air out of the attic space.

Oransi energy efficient whole house fan with damper box

Energy Efficiency and Whole House Fans: Finding the Answer

The main advantage of a whole house fan is that you can cool the home without running the air conditioner, which is almost always more expensive to operate than the fan. But that's a bit of a broad statement.

If you're a homeowner, it's not enough to know that something is efficient, you want to know how efficient it really is. You want numbers, so we'll do our best to give them to you.

Green Building Advisor, an online source for home energy efficiency, says that the typical whole house fan uses about 200 to 700 watts, only 10 to 15% of the power drawn from a central-air-conditioning system, which usually use about 2,000 to as many as 5,000 watts.

They also say that when the outside air is cool enough, especially in the evenings, a whole house fan can cool your home in about an hour, making them nearly as effective as air conditioners.

So, what does that mean in savings?

The answer is still tricky, because the cost savings will depend on how much you use the fan compared to the time you would otherwise be using the air conditioner, as well as your local energy costs, which can vary widely across the country.

The National Renewable Energy Laboratory also provides information on whole house fans and their energy efficiency. According to one of their information sheets, operating a "properly sized 2-ton air conditioner with a seasonal energy efficiency ratio (SEER) of 10 in Atlanta, Georgia" costs roughly $.20 per hour of running time. This is about $250 per season. A whole house fan working under the same conditions, however, only costs about $.01 to $.05 per hours.

Over the length of a summer, this can add up to significant savings...

If we use their estimate of 1,250 hours of run time per season, this means you would spend somewhere between $12.50 to $62.50 running a whole house fan during the season. This would equal annual savings of $187.50 to $237.50. Multiply this over a longer summer and even some years and the savings are quite large.

Another source of information we can look at is, an online source of information that focuses on a wide range of home-building and improvement topics. They say that whole-house fans use about a quarter of the power used by central air-conditioning. They also claim that whole house fans are relatively affordable compared to costs as high as $4,000 for an air-conditioning system.

Finally, let's take a look at some information from House Logic, a site for homeowners, buyers, and sellers, which helps us understand the cost of installation. Installation, however, can run the price as high as $1,000+, and you may also need to pay for ventilation. To help reduce the cost, you may be able to receive local tax incentives that encourage energy-efficiency changes. These costs should be factored into any financial savings when you consider a whole house fan.

thermostat whole house energy efficiency

Is Your Home Right for a Whole House Fan?

While whole house fans are excellent for improving overall home efficiency, not every house is perfect for these products. Most homes will benefit from these appliances, but you need to make sure your house is right before you purchase and install a whole house fan.

First, whole house fans will require you to keep the windows open when the fan is in use. If you have any security concerns, you may not be comfortable leaving the windows open, which makes using the fan a problem. Security bars could help, but this is another added cost for whole house fan installation. There is also the fact that outside air can be polluted from vehicles or industrial pollution, so you may not want to keep the windows open at certain times.

Because whole house fans create a depressurization, there is also a concern for any vented appliances located in the home. Gas fireplaces, for example, should be completely sealed off before using the whole house fan. If not, the air flow created by the fan could pull harmful gas into the living space, creating a significant health concern.

While few homes have furnaces or water heaters located in the attic, if your home does you may need to have it moved, which means a significant and potentially-costly overhaul of your home's HVAC system.

All of these issues, however, can be addressed by whole house fan and home improvement experts. Talk with a professional to see if your home is right for a whole house fan and you may find that the savings are more than you expected.

Whole House Fans May Require Use of an Air Purifier

Because whole house fans rely on outside air to create circulation, it may be necessary to use air purifiers in your home. While the fan is running, air from the outside, which can hold trace amounts of pollen, dust, vehicle exhaust, and smoke, is pulled into the home. This means you could be adding contaminants to your indoor air, and you may need to use an indoor air purifier to remove these pollutants.

For example, if you use a whole house fan and are allergic to pollen, you will likely want want one of our air purifiers for allergies. The Mod+ air purifier, for example, removes over 99% of all airborne particles and can effectively clean a room of 600 square feet.

With proper air purification, many of the particles that are pulled into the home while using a whole house fan are trapped. This eliminates, or at least reduces, one of the main downsides of using a whole house fan to keep you home cool.

Get Reliable Information on Air Purifiers and Whole House Fans

If you want more information on using whole house fans in your home, or how air purifiers can create clean air while the fan is running, contact Oransi today. Our helpful staff will ensure you have the right information to make a fully informed decision.

From air purifiers to advanced filters, we have everything you need for a home full of clean, healthy air.