Leaving your furnace fan continuously on through an Illinois winter is usually the better setting, not the wasteful one. Most homeowners assume the opposite and flip to “Auto” to save money. Whether that holds true for your home comes down to two things: the age of your furnace and the condition of your ducts.
Some people believe a fan that never shuts off signals a problem with the heating system. Here, the Leith Heating and Cooling experts explain why you may want to keep the fan running all season and when you should not.
We are a trusted furnace company in Elgin, with more than 400 five-star reviews and a reputation for prompt, high-quality service. As a veteran-owned and family-operated company, we put our training to work so local families stay comfortable all year. Whether you need a new furnace, an emergency repair, or annual maintenance, call us at (847) 860-7092.
Key Points
- Running the furnace fan continuously mixes warm and cool air, which evens out temperatures between floors.
- The more the fan runs, the more air passes through the filter, so indoor air quality improves.
- ENERGY STAR-rated furnaces are designed around a fan that runs all the time, so “On” can cost less than “Auto.”
- Fewer starts and stops mean less wear on the blower motor.
- Switch to “Auto” if your furnace is more than ten years old, your ducts leak, or the house sits empty most of the day.
What Is a Furnace Fan?
Most modern central heating systems rely on forced air. The system blows heated air through your ducts and vents to warm the house, and a fan is the most efficient way to move it.
Furnace fans either run continuously or switch on automatically when it is time to circulate heated air. Your thermostat setting decides which. If the fan setting reads “Auto” or “Off” and the fan runs anyway, that points to a problem worth a professional look.
Benefits of Running the Furnace Fan Continuously in the Winter
Setting the fan to “On” runs the furnace fan continuously, and that pays off four ways for your comfort, your equipment, and your utility bill.
Improved Air Circulation
Hot air is lighter than cold air, so it rises and leaves your upper floors warmer than the lower ones. A running system counteracts that. The furnace pulls in both cool and warm air and mixes them, which heats the house more evenly.
The result is fewer cold spots downstairs and fewer overheated rooms upstairs. Every room holds a consistent, comfortable temperature.
Better Indoor Air Quality
A running fan pushes air through the furnace filter, and the filter strips out contaminants. The more the fan runs, the cleaner your indoor air gets, especially when you pair the filter with UV light installation in Elgin.
One caveat: a fan that never stops dirties the filter faster. Plan on changing it more often.
Lower Utility Bills
This one sounds backward, but an efficient fan running all the time can cost less than a less efficient one cycling on demand. ENERGY STAR-rated furnaces meet strict energy usage guidelines built around a continuously running fan. An older model is a different story, but if your furnace is only a few years old, heating specialists recommend leaving the fan on.
Reduced Wear and Tear on Equipment
Running a furnace fan continuously in winter reduces wear because the motor is not constantly starting and stopping. Frequent starts stress any motor, and every time your blower kicks on, its internal components take more wear.
Most modern furnaces have fans designed to stay on, so leaving them running preserves their lifespan. Annual furnace maintenance in Elgin, IL keeps that blower motor in shape for a full season of continuous running.
Not sure whether running the furnace fan continuously fits your system? Our NATE-certified technicians will look at your furnace and your ductwork and tell you which setting costs you less. Call us at (847) 860-7092.
When To Use the Auto Setting Instead
Most furnaces benefit from running the furnace fan continuously in the winter, but three situations call for “Auto” instead.
You have an older furnace.
New furnaces benefit from leaving the fan on. If yours is more than ten years old or is not an ENERGY STAR-rated model, that setting may cost you more. “Auto” uses less energy on older equipment.
The ducts have leaks.
Have your ductwork inspected for leaks before running the furnace fan continuously in winter. Leaky ducts stop the heating system from working efficiently, and you will pay to heat your attic. Duct leaks turn up even in newer homes, so ductwork repair and replacement is worth handling before you change the setting.
No one is home most of the day.
If your family is out most of the day, or you are away on vacation, set the fan to “Auto.” That is especially true with an older or less efficient system, and it saves money by preventing wasted energy.
Rely on Leith Heating and Cooling for All Your HVAC Needs
When something goes wrong with your heating system, our HVAC contractors handle the repair, the maintenance, or the replacement. Every job gets high-quality parts and materials.
Residents of Elgin and the Fox Valley call our team for the experience that keeps their HVAC systems in peak condition. We aim to exceed what they expect from us.
Call Us for Service Today
A reliable furnace matters through a cold Illinois winter. Call at the first sign of an issue and we will make the repair before it turns into a cold night.
Our affordable maintenance plans keep your furnace running efficiently all season, with upfront pricing and a 100% satisfaction guarantee behind the work. Schedule your appointment today or call us at (847) 860-7092 to reach one of our award-winning licensed and insured HVAC technicians.