Should I Leave My AC Fan On?

While leaving your AC fan on 24/7 or setting it to “auto” is a debated topic across the industry, there are pros and cons to either keeping the fan running or setting your AC to auto. Here’s a look at both, and our recommendation so you can get the most out of your HVAC system.

Setting Your AC Fan to “On”

When you set your HVAC fan to “on” you’re essentially telling it to keep running 24 hours a day, 7 days a week regardless of which heating or cooling setting it is set to. Here are a few good reasons to do so:

Keeping the fan running allows for more even distribution of heating and cooling as it helps circulate the air if you have cold or warm spots in your house, such as in a bedroom or above a garage.
With less frequent starts and stops of the fan, the stress on your unit is reduced and can potentially extend its lifespan.
Leaving the fan on 24/7 ensures that your hope has cleaner air, as the air is pulled through the filtration more often, which could be beneficial for people with allergies.

While keeping your AC fan on 24/7 might be more energy-efficient, here are a few downsides to leaving the fan on all the time:

It could cause your energy bills to be higher. The average AC unit has a 500-watt fan which can use almost as much energy over the course of the year as your refrigerator.
In the summertime, the ducts in the attic and close to your home’s walls can fill with warm air resulting in the fan blowing hot air into your house. Your AC will have to work harder to counterbalance that extra heat.
In the winter, you might feel cold air coming from your vents.
Your furnace filter can clog up more quickly.

Related: Should I Turn My AC Off When It’s Nicer Outside?

Setting Your HVAC Fan to “Auto”

Setting your AC fan to “auto” means that your fan will run when directed to by the unit. Here are the pros to using this approach:

This is more cost-effective because you will lose less energy. The fan will run the least amount of time that it is needed at its slowest speed.
The filter will last longer.
You will notice better dehumidification in your home. When the unit is set to “auto” it will allow moisture to drip from the cooling coils and drain outside.

Cons to the “auto” setting:

You might notice an uneven distribution of heating and cooling because once the thermostat detects that your home is up to temperature, the fan will stop moving air to other spaces in your home.
The fan can wear out faster due to more frequent starts and stops.

Which HVAC Fan Setting is Best?

Since every home and personal preference is different, when it comes to keeping your air conditioner fan on or on auto, it depends. For those who have young children that are home most of the day, or for those who suffer from allergies, keeping the fan running 24/7 can be a good option. On the other hand, if you work away from home during the day, the “auto” setting might be beneficial since it reduces your energy costs.

Super Heat & Air Tip: Many of the newer thermostats on the market have a “circulate” option that allows you to set the fan to “on” for a certain amount of time each hour. The blower will automatically run during the programmed time and will increase your comfort, but help keep the electric bill down.

Further reading: The Benefits of Using a Smart Thermostat

Tampa Bay Heating & Cooling Specialists

With our Super Fast Guarantee, we are ready to help make your home as comfortable as it can be! From seasonal HVAC maintenance to emergency repairs and duct cleaning, we do it all! For reliable super fast service that you can trust, call the pros at Super Heat & Air! 813-322-6823