Furnace Fan Guide: When to Run the Furnace Fan

Whenever you’re faced with winter’s harshness, you blast the heat in your home to make yourself cozy. Generally, as the weather changes, heat isn’t necessarily required, which means you won’t be using the furnace anymore.

However, depending on your thermostat’s model, you may have the option of turning the furnace fan on or off. It may sound strange, but you can actually run your furnace fan throughout the summer and not just when it’s cold outside. Let’s talk about why.

Should You Run a Furnace Fan Continuously?

To run, or not to run—that is the question. The answer, however, really depends on your individual situation and furnace fan. In some cases, like if you have an old model or if high temperatures make conditions dangerous, running your fan continuously is not a good idea. But in most other cases, continuous use of the furnace fan actually has a lot of benefits that will sway many homeowners to the affirmative.

Pros of Running Your Furnace Fan Continuously

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For homeowners, the word “benefits” is a tantalizing promise. You’re always looking for ways to make your space more comfortable and efficient.

So if you’re planning on running your furnace fan continuously, it comes with the following benefits:

Lowering Your Electric Bill 

We know it doesn’t seem like it makes sense to leave your furnace fan on all the time since it uses up electricity—but a slight change can help lower your electric bill.

Here’s a little secret—you actually use more power when your air conditioner is set to “auto” because of the constant starting and stopping.

This happens because your AC is trying to keep the room cool. But using it with your fan will help circulate the air in your home, saving you from relying on your unit and lowering your overall costs.

Removing Dust and Allergens

We’ve all had our battles with dust at some point. No matter how much cleaning gets done, it always seems to pop back up! Unfortunately for others, it can be a hassle, especially when allergy season rolls around.

But your furnace fan may be able to help you with those allergens. Dust and other contaminants can reside in the air, making breathing harder. To eliminate these issues, your furnace fan filters the air in your home, meaning it will filter out any irritants as well.

Reducing Odors

Have you ever walked into your home one day and caught a whiff of an unpleasant smell? It could be the result of mold, mildew, or indoor smoking. When these pollutants get trapped inside for extended periods without proper filtration, you’ll smell a musty odor whenever you enter a room.

However, furnace fans that run continuously can reduce these odors since air is constantly filtered.

Limiting Humidity in Your Home

There’s nothing worse than leaving one area of your home and walking into another that makes you uncomfortable because of the humidity. It can be a double whammy if you’ve come from outside during a hot day.

But luckily, furnace fans can limit humidity in your home. As the air runs through your air conditioner’s evaporator, it pulls the moisture out.

There are plenty of reasons why you should keep your furnace fan on throughout the summer. By doing so, you’ll create a cleaner environment for your household.

Running a Furnace Fan Continuously in Summer

Your furnace fan, also known as a “blower,” is an integral part of your HVAC system, which pushes cold and hot air through your vents. Your system likely has two settings, “auto” and “on,” which dictate how often your system is running.

Most homes have their furnaces in the attic, which makes that area the hottest in your home. So warmer air may come out of your vents.

However, it would help if you switched your furnace fan to the “on” setting throughout the summer for these reasons:

• Prevents hot spots in your home

• Helps your HVAC system maintain an efficient temperature

You may be thinking that continuously running your furnace fan will ruin it and make your electric bills skyrocket. After all, one of the most common furnace problems people deal with is having a blower fan that won’t turn off. But it won’t be an issue if you have a newer system. You can always check with your local furnace installer if you’re unsure of the age of your model.

Cons of Running Your Furnace Fan Continuously

There will always be a debate about auto versus on for thermostat usage.

While it’s possible to run your furnace fan continuously, it still has some slight drawbacks such as:

• Running older units can cause your electric bills to rise

• Ducts and walls can fill with hot air, causing you to use your AC more frequently

• Your furnace filter may clog more quickly

You should also be cautious of running your furnace fan continuously if you have ductwork in your attic and it’s a hot summer day. Since heat rises, the temperatures up there could reach around 140 degrees Fahrenheit. As a result, the fan could pull heat from the attic into your home.