How Does an Attic Fan Work? Understanding the Pros and Cons of Attic Ventilation Fans

If you're looking for ways to improve your home's energy efficiency during the summer months, you may have come across the idea of installing an attic fan. Attic fans are designed to push hot air out of your attic, reducing the strain on your air conditioning system and making your living space more comfortable. But how do attic fans work, and are they really worth the investment?

What is an Attic Fan?

An attic fan is a type of ventilation fan that is installed in your attic to help regulate the temperature and improve air circulation. These fans are typically mounted on the roof or gable vent and can be powered by electricity, solar energy, or even wind. The purpose of an attic fan is to remove hot air from your attic and push it outside, while also drawing in cooler outdoor air to replace it.

How Do Attic Fans Work?

Attic fans work by pulling hot air out of your attic and pushing it outside, which can help reduce the temperature in your attic (obviously) and the rest of your home. The fan accomplishes this by creating negative pressure in your attic, which draws in cooler outdoor air through attic vents and other openings in your home. This creates a continuous flow of air that helps regulate the temperature in your attic and prevent ice damming during the winter months.

There are two types of attic fans: mechanical attic fans and natural attic fans. Mechanical attic fans are powered by electricity and typically have a thermostat or humidistat that turns the fan on and off based on the temperature or humidity levels in your attic. Natural attic fans, on the other hand, are more like your temperamental (and lazy) cousin. These types of attic fans are powered by wind and don't require any electricity to operate. The downside, of course, is that no wind means no fan activity.

In either case, attic fans are typically installed on the roof and work by using the wind to pull hot air out of your attic.

Pros and Cons of Attic Fans

Attic fans offer several benefits, such as improved energy efficiency, reduced energy bills, and increased comfort in your living space. By removing hot air from your attic, attic fans can help reduce the workload on your air conditioner, which can lead to lower energy bills. They can also prevent ice damming during the winter months, which can cause damage to your roof and home.

However, there are also some potential drawbacks to consider. Attic fans only work when the temperature outside is cooler than the temperature inside your attic, which means they may not be effective during extremely hot weather. Additionally, attic fans can create negative pressure in your attic, which can draw conditioned air from your home into your attic and potentially reduce the effectiveness of your air conditioning unit.

This is why we do not recommend using an attic fan as your primary or singular source of cooling during the hot, humid months of summer. They are designed to be used as a supplemental addition to your HVAC unit, not a replacement.

Attic Fans Vs. Whole House Fans: What’s the Difference?

Attic fans and whole house fans are often compared, as they both serve the purpose of reducing indoor temperatures and improving air quality. However, they work in different ways and have distinct advantages and disadvantages.

An attic fan is installed in the attic space and is designed to push hot air out of the attic, which can help to cool the rest of the house. Attic fans are generally less expensive than whole house fans and are easier to install, as they do not require significant changes to the structure of the house.

On the other hand, a whole house fan is installed in the ceiling of a home and is designed to pull cool air from the outside into the living space, while pushing hot air out through attic vents. Whole house fans, like the QuietCool Whole House Fans are like attic fans on steroids; they’re generally more effective at cooling the entire home than attic fans, as they bring fresh air into the living space, whereas attic fans only circulate the air in the attic.

However, whole house fans can also be more expensive and more difficult to install than attic fans. They also require windows or other openings in the home to allow fresh air to enter, which may be a disadvantage in areas with high levels of outdoor pollution or noise.

When deciding between an attic fan and a whole house fan, it is important to consider the specific needs of your home and the local climate. Homes in hot, dry climates may benefit more from an attic fan, while homes in areas with cooler nights and lower humidity may benefit more from a whole house fan.

Ultimately, both attic fans and whole house fans can be effective ways to reduce indoor temperatures, increase energy savings and improve air quality. The best choice, however, will depend on the specific needs and circumstances of your individual home.

Installing an Attic Fan

If you're interested in installing an attic fan, there are a few things to consider. First, it's important to determine the size of fan you need based on the size of your attic and the climate in your area. Attic fans are typically rated by the amount of cubic feet of air they can move per minute (CFM), so make sure you choose a fan that is appropriate for your needs.

Next, you'll need to decide on the type of fan you want to install. Mechanical attic fans are typically more expensive, however they offer more control over the fan's operation. In contrast, natural attic fans that may save you more money upfront are generally not as effective in all climates. Finally, you'll need to decide on the location of your fan and how it will be powered.

Attic Fans Recap:

In summary, attic fans can be a great way to improve the energy efficiency of your home and increase your comfort during the summer months. By drawing in cooler outdoor air and pushing hot air out of your attic, these little fans can reduce the workload on your air conditioning system and potentially lower your energy bills in the process! However, it's important to consider the potential drawbacks of attic fans as well, such as their limited effectiveness during extremely hot weather and the potential for negative pressure to draw conditioned air from your home into your attic.

If you’re on the fence about deciding between an attic fan and a whole house fan, it's important to consider the specific needs of your home and the local climate. While attic fans are generally less expensive and easier to install, whole house fans may be more effective at cooling the entire home by bringing fresh air into the living space. Ultimately, the best choice will depend on the individual needs and circumstances of your home. If you're considering installing an attic fan, be sure to carefully consider the size, type, and location of the fan, as well as how you intend to power it.

Ready to pull the trigger on your own attic fan or upgrade to a QuietCool Whole House Fan? Connect with one of our HVAC techs today, and we’d be happy to get an appointment scheduled for you ASAP!