Potential Fan Motor Wear: Your furnace fan's motor is not designed for constant use. Running it continuously may lead to more frequent maintenance and repair needs. However, the added comfort and air quality benefits often outweigh these concerns.
You can, though those big furnace fans have surprisingly poor energy efficiency. They don't use efficient electric motors and there's a lot of load due to all the ducting.
Some homeowners naturally worry about the risks of a breakdown if they run the fan all the time, but this will not be a concern for you if your HVAC system was properly installed and maintained. The only possible exception here is a very old fan system, which should generally be replaced in the near future anyways.
Since the AUTO setting means the fan is only engaged when the system is on, rather than constantly blowing, AUTO is the most energy-efficient option between the two settings. This means you'll be using less energy and saving money on your electric bill by using the AUTO setting.
In the summer it is okay to run the fan on continuously because it allows the house to stay cool as it circulates the cool air. This is not a good idea in the winter though as it cools the house down faster and does just that keeps turning the system on/off continuosly fighting the thermostat to satisfy.
The average kWh in the US costs about $0.12 so it costs about $43 per month, or about $520 per year, to run a fan continuously. At this point, it should be pretty obvious that AUTO costs less than ON but let's math it out to its logical conclusion.
The fan will constantly blow air into your room if you have the thermostat turned “ON.” If it is on “AUTO,” it will only turn the fan on when heated air needs distribution. So yes, running HVAC continuously throughout the day and night is perfectly safe!
It could cost you hundreds of dollars a year. The average unit has a 500 watt fan, which uses almost as much energy over the course of the year as a refrigerator, resulting in a $50/month bill.
"Most electrical fans are designed to be able to run continuously for several hours at a time, for example overnight or during the day, but you'll also need to keep in mind doing that continuously for long periods can cause wear and tear on the motor and other components, shortening its lifespan," continues David.
Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.
When it comes to whether you should set your furnace fan to “on” or to “auto” in winter, the answer for me is “auto” because it's the move that has the most to do with energy efficiency. It is not, however, the only thing you can do this winter to bolster your HVAC system's energy efficiency.
The blower motor is particularly sensitive to dust and dirt; when it gets too dirty, it can't ventilate itself and may overheat.
In most cases, your HVAC system does not pull air from outside when it is heating or cooling your home. Instead, it recirculates the air inside your home.
Running it continuously may lead to more frequent maintenance and repair needs. However, the added comfort and air quality benefits often outweigh these concerns. Noise: If you're sensitive to background noise, you might find the constant hum of the furnace fan bothersome.
You can run your system's fan independently of heating or cooling. So your system doesn't need to be actively heating or cooling to run the fan. However, you can only run the fan when your thermostat is set to a temperature mode (like Cool mode, for example).
One of the easiest ways to reduce dust in your home is simply to turn on your HVAC fan after dusting or vacuuming by switching your thermostat from “auto” to “on.” This allows your HVAC system's filter to remove any airborne dust from your home before it can settle or continue to circulate through your home.
Do not run your whole house fan during the day unless the temperature outside is cooler than the house is inside, though you may want to run the fan during the day to push air out of the attic. To do so, direct airflow from either the basement or the shady side of the home.
A ceiling fan is made up of different parts and pieces, and they will wear out over time. Sure, your ceiling fan can run throughout the day and night without issue, but running it for several days or months on end may not be the smartest choice and will reduce the overall lifetime of your fan.
Avoid leaving your fan running overnight or while you are out of the house. Ensure you have working smoke alarms on every floor of your home. Once you've had your electric fan for a few years, think about replacing it as older motors can overheat.
Running the Fan Continuously
This offers benefits for your home such as: Improved air circulation throughout your living spaces. Enhanced indoor air quality by filtering air continuously. Reduced motor stress by minimizing frequent starts and stops.
Turning the fan on in the evening after a hot day and opening the window to let in cool air will cool the home off quickly. Circulating air with the blower fan on your furnace also evens out the air temperature throughout your home cooling rooms on upper levels.
The fan only turns on when cooling or heating is required. If you are generally as comfortable in one room of your home as the next, you'll want to use the AUTO setting. The AC fan kicks in when needed and stops running when the job is done.
The AC uses less energy in fan mode than when cooling. But running the fan all the time can increase the amount of maintenance your HVAC system might need.
Leaving the fan running reduces wear and tear on the motor since it's not starting and stopping repeatedly. It's also beneficial to boost filtration, but leaving it on this setting has more drawbacks than benefits. When it runs nonstop, the fan consumes more energy, and the air filter needs frequent replacement.
Running a fan throughout the day is inexpensive—much lower than the cost of running an AC unit alone—and using both in conjunction with each other means that you won't have to keep your air conditioning running all day.