Should an Attic Fan Run in the Winter?

Should An Attic Fan Run in Winter?

If you have an attic fan, you probably think of it as primarily a tool to keep your home cool in the summer.

But should an attic fan run in the winter? 

Though it may come as a surprise, there are a few reasons why you should run your attic fan in the winter.

Let’s look at some of the benefits to running an attic fan in the winter and how you can use your attic fan year-round to keep a healthy, comfortable home.

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Benefits of running attic fan in winter

So why should you run your attic fan in the winter?

These are the key benefits of running an attic fan in winter.

Prevents mold and mildew accumulation

During the winter months, it’s easy for moisture to gather in your attic. When it’s there for long enough, mold and mildew will inevitably begin to grow. An attic fan brings in dry winter air to keep damp air in check, preventing mold and the health concerns associated with it.

Breaks up ice dams

Heat trapped in your attic while you’re blasting the heater during the winter can cause snow to melt. It then can re-freeze quickly, creating ice dams. By allowing the dry air into your attic, it regulates temperature and prevents hard freezing.

Read our guide for more information on attic fans can and ice dams. 

Keeps insulation intact

Moisture in your attic can cause more than mold and mildew. It also causes wet insulation, which causes it to lose thermal resistance, rendering it pretty much useless. The drying effects of the attic fan can prevent this damage.

What settings should my attic fan be on in winter?

In the winter, your attic fan’s humidistat should be kept at 70-75% unless you live in an extremely humid area.

You should also not run your attic fan for more than a few hours at a time, as this could waste electricity.


Your attic fan is just as useful in the winter as it is in the summer. Follow these tips and reap the benefits of using your attic fan year-round.