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Can You Run an Attic Fan with the AC On? (Explained)

If you have an attic that you hardly visit and use to store things away, you may, at one point, think about removing the attic fan.

If you’re roaming around similar thoughts, you’d want to reconsider things. This is because, your attic fan is one of the most important tools in your house, particularly if you have ac.

Running an attic fan with the ac on

Running an attic fan with ac on is considered to be both safe and prudent. This is because an attic fan works to keep the temperature of the house regulated by getting rid of the hot air. This cools the house, increases ac efficiency, and cuts electricity costs as well.

Since you’re here and invested in reading this, we are under the impression that you must already have an attic fan. And if you do not have one while you have an air conditioning system cooling your home, we suggest you get one attic fan that works.

An attic fan is so more than just a fan you would use to turn on when you visit the attic once in a while. As you must have realized, your attic is the hottest space in your home. It’s the area where all the heat is trapped from the roof, protecting the main ceiling of your house.

Now, if you keep the temperature of your attic to a minimum, it would only mean that the temperature of your house will also be decreased. How an attic fan helps is simple. It draws out any hot air from the attic to push it through a window or vent outside.

It also draws out stale air through the dormers. With the attic fan working to keep the attic cool, the temperature of your home below the ceiling is also lowered. This means that the air conditioner now has to work lesser hours to reach the cool temperature that you would desire.

Without an attic fan, the attic can reach temperatures of 160 to 170 degrees during the summer season. Around these times of the year, you are using your ac day and night.

If the attic is hotter by so many degrees, it would also mean that your home is much hotter as well, indicating that your air conditioner would be working overtime to compensate for the heat.

When your air conditioner is working fewer hours, it only means that you are cutting off on electricity bills and saving yourself a good amount simply by turning on the attic fan at the right times.

An increase in energy bills is not the only concern to have when you don’t have an attic fan running when the ac is on.

Other than compromising on the efficiency and performance of your ac, your ac may also need more maintenance for being overworked. Clogged filters and air leaks could become more frequent as well.

You can also avoid a noisy air conditioner if you use an attic fan just to ease the pressure on the cooling system. With that mentioned, you do not have to turn on the attic fan indefinitely and you should only use it when the ac is turned on.

If you are wondering about the safety of turning an attic fan simultaneously with an air conditioner, let us tell you that it is safe and advisable to do so.

Is it safe to run an attic fan all night with an AC on?

The primary purpose of an attic fan is to get rid of the hotter air to replace it with cooler air. Now during the night time, the temperature falls and the outside, as well as the attic, becomes much cooler.

In such cases, even with your ac on, it would not be a good idea to turn on the attic fan all night long. Other than the diminished need for it, you would also need to make sure that your attic fan is well rested.

Keeping in on for all night all could be risky as the fam motor could possibly blow out. Moreover, you are only making the attic fan less energy efficient than it can be by using it all night.

If you are turning on the ac all night and suspect your attic is too hot on a summer night, you can turn it in for some time and then turn it off.

If you wish to turn it on in bursts throughout the night, you may want to make sure that you keep it off for long enough so that it can cool down.

How long should you run an attic fan with an on?

With an ac turned on, you might think that you have to keep your attic fan running throughout. Remember that an attic fan needs to be able to draw out the warm air and make the attic space cool.

Hence, more technically, you would need to turn on the attic fan for as long as it takes for the fan to accomplish its job, that is to dispose of the warmth and cool the attic.

This could take anywhere from 15 minutes to 40 minutes, depending on a few important factors. Among these factors, one of the most determining ones is how hot your attic can get.

The climate, direction in which the house is facing and time of the day will all play a part. During the evening, turning on the attic fan for a good 15 minutes can be enough since it gets cooler.

The strength of the fan and the total area of the attic would also vary the time you need to run the fan while the ac is on. A bigger house with a bigger attic would need the fan to run longer than a smaller house with a smaller attic.

What happens if you use an attic fan with an AC on?

With mostly all advantages, there are myriads of effects, both long term, and short term, that an attic fan can have when used with ac on. Here are some of what happens if you use an attic fan with an AC on.

Keeps the house cooler:

If you have an ac on in your living room, it does not mean the rest of the rooms in the house do not need cooling.

If you have an attic fan turned on during the time ac is on, you would rest assured that the house is significantly cooler on its own. While this has many pros including comfort and efficiency, a hot roof can be damaging as well.

The ac does not overwork:

As the attic fan works to draw the hot air out of the attic to replace it with cooler air, the attic drops in temperature by several degrees. In turn, the roof and hence the house was made cooler.

This also means that the ac does not have to work more hours to cool down the house. An overworked air conditioner loses its performance over time with problems like leaked units and clogged filters.

You save on electricity costs:

With your ac working fewer hours than it should have been without an attic fan, you can save a lot on your energy costs.

How do you use an attic fan with AC?

Here are a few steps to follow if you wish to use an attic fan with ac on:

Ensure vent:

To use an attic fan with ac, you would first need to make sure that there is a vent or a window through which the attic fan can draw out the hot air. Before anything else, open the windows in the attic.

Turn on fan:

You may want to turn on the attic fan prior to turning on the ac so that the attic and hence the house is already cooled down before the ac gets working.

Run fan for 30 mins:

You may want to run the attic fan in bursts from 15 to 30 minutes at a time or for as long as the attic becomes completely cool. Cycle it every few hours, in turn, to keep the humidity in check

Keep it rested:

Keep the attic fan rested during cooler days or nights. You would have to let the motor fan cool down before you again turn it on. During the summer days, you would want to turn on the fan every few hours.

Final Thoughts

You can turn on and run an attic fan with an air conditioner on. It is sensible to keep the attic fan running if you use an ac so that the fan can draw out the hot air and transfer it out the window. This would prevent the ac from overworking, keeping the heat in the house regulated.