Keeping your home toasty warm during the winter is a priority. But when temperatures plummet, is it better to keep the furnace blower set to “On” or use the “Auto” setting instead? Either setting has pros and cons, and the answer depends on the system and its condition.

Some people believe running a furnace fan continuously during the winter is detrimental to the system and a sign of a problem with the heating system. Here, the Leith Heating & Cooling experts explain why you may want to keep the fan running all season long and highlight a few situations when it’s not a good idea.

We are Elgin’s trusted furnace company, with more than 400 five-star reviews and a reputation for high-quality, prompt, and effective service. As a veteran-owned and -operated company, we put our experience and training work to ensure local families stay comfortable all year round. Whether you need a new air conditioner or furnace, emergency repairs to your current system, or want to schedule annual maintenance, call us at (847) 860-7092 to reach our team of expert contractors. 

What Is a Furnace Fan? 

Most modern central heating systems rely on forced air. In other words, the system blows heated air through the ducts and vents to warm your home. A fan is the most common and efficient way to do this. 

Furnace fans may run continuously or turn on automatically when it’s time to circulate the heated air. It all depends on how you set the thermostat. If you have the fan setting on “Auto” or “Off,” and the fan runs continuously, that’s a sign of a problem that requires professional attention. 

Benefits of Running the Furnace Fan Continuously in the Winter

Keeping the fan switch set to “On” ensures that the furnace blower stays running, which offers several benefits to your comfort, the system, and your wallet. Let’s go through them below.

Improved Air Circulation

Because hot air is naturally lighter than cold air, it rises, making the upper levels of your home warmer than the lower. When it’s running, the heating and cooling system can help counteract this effect. Keeping the furnace fan turned on supports more even heating since the furnace pulls both cool and warm air in and mixes them. 

Essentially, running the furnace fan helps prevent cold spots throughout your home and overly warm upper levels. You enjoy a consistent, comfortable temperature in every room. 

Better Indoor Air Quality

When the furnace fan runs, it pushes air through the furnace filter, eliminating contaminants. The more the fan runs, the more the filter cleans the air and the better the indoor air quality, especially when you pair the filter with UV light. One caveat: Continuously running the fan means changing the furnace filter more frequently since it will get dirty and clogged more quickly. 

Lower Utility Bills 

It may seem counterintuitive, but continuously running an efficient furnace fan may save energy and cost less than operating a less efficient model as needed. ENERGY STAR-rated furnaces meet strict energy usage guidelines based on a continuously running fan. This may not be the case for an older model, but if your furnace is only a few years old, heating specialists recommend keeping the fan on.

Reduced Wear and Tear on Equipment

Running a furnace fan continuously in winter reduces wear and tear because it’s not always turning on and off. Frequent starts stress any motor, and the more often your furnace blower kicks on, the more wear and tear its internal components will sustain. Again, most modern furnaces have fans designed to stay on, so it’s better to keep them running to preserve their lifespans. 

When To Use the Auto Setting Instead 

Although most furnaces benefit from running the furnace fan continuously in the winter, there are some cases in which it’s better to select the “Auto” setting. 

You have an older furnace.

New furnaces may benefit from keeping the fan on, but if your furnace is more than ten years old or is not an ENERGY STAR-rated model, doing so may be more expensive. Setting the thermostat to “Auto” can use less energy and be more cost-effective. 

The ducts have leaks.

If you haven’t inspected your ductwork recently, have it checked for leaks before running the furnace fan continuously in winter. Leaky ducts prevent the heating system from working efficiently, and you’ll waste money running the fan all the time. Duct leaks are common even in newer homes, so schedule regular inspections to avoid costly problems.

No one is home most of the day. 

If your family is busy and away from home most of the day, or you’re away on vacation, you may want to set your furnace fan to “Auto,” especially if you have an older or less energy-efficient system. This can save money by preventing wasted energy.

Rely on Leith Heating & Cooling for All Your HVAC Needs 

If you have any problems with your heating system, you can rely on the experienced HVAC contractors of Leith Heating & Cooling for fast, reliable repairs, maintenance, and system replacements. We strive to exceed customer expectations, using only the highest-quality parts and materials to tackle every job. Residents of Elgin and throughout the Fox Valley turn to our team for our unparalleled knowledge and experience to keep their HVAC systems running in peak condition.

Whether you have concerns about your furnace fan or want to know reasons your furnace might be leaking water, we’re here 24/7 for all your heating and cooling needs. 

Call Us for Service Today

A reliable furnace is essential during a cold Illinois winter. Don’t risk a costly breakdown — call Elgin’s premiere HVAC providers to make repairs at the first sign of an issue. We also offer affordable and convenient maintenance plans to keep your furnace running efficiently and provide peace of mind. 

Call us today at (847) 860-7092 to schedule service with one of our award-winning licensed and insured HVAC technicians.

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