Should the Fan Be On When the Heat Is On?

Heating costs are high and are continuing to rise. Therefore, homeowners in the Portland area often weigh improved comfort over saving. Operating a heating system is complicated during the wintertime. A common consideration is whether the fan should be on when the heat is on, or to set the thermostat to auto.

To clarify this, let’s look at what your thermostat’s “on” and “auto” settings mean. The two differ in that:

• “On” allows the furnace fan to run continuously, whether the heater is running or not.
• “Auto” means the fan will run until the furnace reaches the temperature set on the thermostat.

Benefits Of Keeping the Fan On

Ultimately, the best setting depends on your home and your preferences. However, here are some benefits of leaving the fan on with the heat:

• Improved Circulation: The fan helps circulate heat. During the winter, the “stack effect” can cause parts of your home to be warmer or cooler. That’s because heat tends to rise. Areas with more sun exposure can be warmer as well. Circulating the heat helps avoid having warmer or cooler spots throughout your home.
• Better Air Quality: Setting the fan to “on” also means the air will constantly cycle through your HVAC unit’s filtration system. If the filter is changed regularly, fewer particulates will be in the air, further improving comfort. For the best improvements, install a high-efficiency air filter and UV light purifier.
• Less Wear and Tear: The fan built into your furnace has been engineered to run continuously. Its motor tends to wear out when it starts and stops more frequently. Therefore, always running the fan when the heat is on won’t cause your furnace to fail prematurely.

Why People Prefer Their Thermostat’s Auto Setting

While there are downsides to keeping the fan on auto, some can be compensated for. For example, improving insulation or balancing ducts and vents (done by an HVAC technician) can provide more even heating. This includes when the fan starts and stops. 

Also, since the fan is only running part of the time, you can save energy. The fan will run when the furnace is heating your home until it reaches the level you set on the thermostat. Once the system is at temperature, the furnace and fan will shut off. In addition, the filter may last longer because less air is passing through it.

How to Decide Which Option Is Better

If you’re asking “Should the fan be on when the heat is on?”, think about your priorities. Keeping the fan on auto is fine if you prioritize energy efficiency. If comfort and air quality are at the top of your list, keep the fan on. 

But there’s one other option that can provide a balance between the two. A smart thermostat lets you program your furnace, so it’ll turn on when you want it to and run for a predetermined amount of time. Even with the heat and fan running together, this can minimize wear and tear while keeping your house warm and cozy.

Contact Sky Heating & Air Conditioning

Our heating installation, repair, and maintenance specialists can provide professional advice on how to run your HVAC fan. We understand the needs of different types of homes and heating systems. The balance between comfort, efficiency, and durability is important for every Portland homeowner. Sky is here to answer all your questions and is available 24/7 if you need immediate service. 

It’s also important to note every heating system will experience wear and tear over time. That means routine care and the occasional fix are part of owning a furnace or heat pump.

Sky Heating & Air Conditioning is ready to ensure your home is safe, comfortable, and efficient. To learn more about or schedule heating and furnace maintenance services in your area, schedule your appointment online or call 503-673-9083.