Here’s how to choose the best whole house fan. Not only can these helpful ventilation systems help keep you cool, they also help save on energy costs.
Are you searching for the best whole house fan for your home? Whole house fans will keep your home cool at a fraction of the cost of air conditioning. Once you install them in a room, the temperature will naturally drop. We’ll walk you through the pros and cons and help you choose the best option for your home.
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What Is the Best Whole House Fan and How Does It Work?
A whole-house fan is a large electric fan, usually centrally located within a home or other building, that circulates air through the entire place. It pulls in fresh air from open windows and doors and pushes hot air out and into an attic, where it can then escape through attic vents.
The basic concept is simple: An attic-mounted fan pushes hot air out through attic vents and draws cooler, outside air in through open doors and windows. This rapid air exchange—large fans can purge a house of hot air in two to three minutes—not only removes built-up heat but also creates a pleasant breeze.
A whole house fan can turn over the air in a home up to six times an hour, depending on the size of the house.
When you use a whole-house fan, it’s important to open doors and windows. Otherwise, the fan may cause gas-burning appliances, such as your furnace or water heater, to backdraft exhaust fumes and carbon monoxide into your home. Whole house fans are not allowed in all areas. You should check your local building codes before buying one.
Quiet Whole House Fans vs. Attic Fans: What’s the Difference?
Quiet whole house fans and attic fans have several distinct roles. They are both used for home ventilation and cooling. Generally, you can see that whole house fans are installed in the ceiling. According to the U.S. Department of Energy, “Whole house fans pull outdoor air into a home through open windows and exhaust it through vents in the attic and roof.”
An attic fan is made specifically to ventilate an attic, pulling out hot, stale air so that heat and humidity don’t build up. An attic fan helps prevent problems like mold and mildew from the space and even helps extend the life of your roof by preventing problems like ice dams in the winter and excessive heat buildup in the summer.
Whole House Fan Benefits
Whole house fans can save more energy and are environmentally friendly. You can use a fan as a pre-chiller. If you are in a very hot place, run a whole house fan for several minutes before switching on the AC. This fan uses less electricity so that you don’t need to run your AC as long.
If your house is in a dry climate, you can cool down your room temperature by using a whole house fan. Switch on the fan on cooler nights and turn it off during the hottest times of the day. Keep your windows and doors shut.
Whole-house fans aren’t always the best option.. They can’t cool inside temperatures lower than outside temperatures and they don’t dehumidify. If you live in a humid region, you’ll still need to lean on your air conditioner on hot summer days. If you suffer from allergies, the fans can draw in outdoor pollen and dust.
Installation Guide for Whole House Fans: How to Choose the Best One
Be sure to thoroughly follow the installation guide for whole house fans. A local HVAC installer can help you find the fan that best fits your home and climate. Keep in mind that size isn’t everything. Larger fans are great for moving air quickly, but when you weigh the increased size against installation requirements, insulation, appearance, noise and cost, you may opt for a smaller fan. (Depending on your needs and floor plan, several smaller fans may provide better airflow.)
Attic ventilation is almost as important as the fan. A fan won’t work if the hot air doesn’t have an easy way out. Without adequate ventilation, the fan may force hot air down on you. If you don’t want to install additional venting, it may make sense to stick with a smaller fan.
These days, there are several different types of fans to choose from. In addition to the large traditional models, manufacturers have come up with types that are easier to install and better insulated.
Before you buy, contact your utility company to see if you’re eligible for an energy rebate. You may also be able to reclaim a portion of the cost as an energy tax credit on your income taxes.
Pros and Cons of Whole House Fans: Energy-Efficient Home Ventilation
A whole house fan is great for energy-efficient home ventilation. There are several different types of fans to choose from depending on your needs.
Standard fan
Standard fans are the most affordable and widely available. Large-diameter fans are still a good solution for homeowners living in warmer regions. These fans cost less up front, but installation may be more difficult. Moving a joist in order to frame out a box for the fan or installing additional attic venting, might wind up costing more than the fan itself. Another disadvantage is that during the winter, the vented opening works like an open window, giving warm, moist air an easy path out and into your attic. To prevent heat loss, you’ll need to build an insulated box to cover your fan during the off-season.
Pros
- Affordable
- Larger, more powerful
Cons
- Installation can be more difficult
- Heat loss in the winter without adding insulation
Insulated-door fan
If you live in an area with frequent cold snaps, you’ll want a fan that holds in the heat when it’s not in use. Door fans come with insulated (R-22 or R-38) panels that open every time you turn the fans on. This feature not only helps during winter months but also keeps heat out during the summer when you’re running your AC.
These models don’t move as much air as standard fans, but they tend to run quieter, so they can be run all night. Like standard fans, these units are usually installed in a hallway, but some smaller models are specially designed to fit in between or around existing trusses or joists to make installation easier.
Pros
- Insulated panels add to efficiency
- Quieter than standard fans
Cons
- Don’t move as much air as standard fans
- More expensive
Inline fan
Fan/insulated duct units don’t move as much air as standard fans, but by investing in one fan per bedroom, you can provide a breeze effect in the room(s) you most want to cool. The small intake port is not only less obtrusive than the large louvered panels needed with other fans, but also easier to install. (A flexible duct connects the intake port to the fan.) Like insulated door fans, inline fans have damper doors within them that prevent warm air from leaking out in winter.
Pros
- Perfect for single rooms
- Easy to install
- Damper doors
Cons
- Only works for individual rooms and smaller spaces
- Not as powerful
FAQ
How long should you run a whole house fan?
It depends on your house location and the time of day. If it is in the morning or evening, you can run it for 20 to 30 minutes. You should run it longer on warmer days. You need to flush out the hot air properly to get the cooling effect. If you want the maximum capacity of a whole house fan, always check the inside and outside temperatures and run it accordingly.
Can a whole house fan work in humid climates?
You will get less efficiency if you use a whole house fan in a humid climate. If the outside weather is hot and humid, it will pull in the moisture-laden air into your room. So, you will not get the cooling effect that you want.
Sources:
- NREL: “Whole House Fan: How to install and use a whole house fan”
- USDE: “Measure Guideline: Ventilation Cooling”
- USDE: “Whole-House Fans”
- FSEC: “Measured Natural Cooling Enhancement of a whole House Fan”
- NIST Publications: “Savings in Electric Cooling Energy By the Use of a Whole-House Fan”
- The California State University: “Experimental study of whole house fan airflow efficiency”
- USDE: “Cooling with a Whole House Fan”
- USDE: “Attic Ventilation Fans”
