Generally, running the fan for 15-20 minutes per hour is sufficient for adequate air circulation. However, longer fan run times may be necessary for specific conditions like hot and humid weather or improved air filtration.
They should not be left on all the time. Some of the more advanced thermostats might use the fan to better circulate the air post-AC or heat running or pre-cool the home a little by running the fan. But in normal operation, it only runs with the furnace or AC does.
Cons to Keeping Fan Continuously Running:
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.
On a 90-degree day, your AC system might need to run more frequently to maintain a comfortable indoor temperature. Typically, an AC unit should run for about 15-20 minutes per cycle.
A typical AC fan motor uses about 500 watts when it's running. Therefore, if you run the fan continuously for a 30-day month (720 hours), you would use 360,000 watt hours (720 x 500) or 360 kilowatt hours (kWh). Therefore, the fan uses about 360 kWh per month in the ON mode.
Setting the fan speed too low will usually cause the evaporator coil to freeze. If the fan speed is too high, it can cause the AC condenser to short-cycle or turn on and off constantly. This puts a huge amount of stress on the unit and also results in greatly increased energy costs.
Generally, running the fan for 15-20 minutes per hour is sufficient for adequate air circulation. However, longer fan run times may be necessary for specific conditions like hot and humid weather or improved air filtration.
Some of the basics include: turn your thermostat up a couple degrees and deal with 76 to 78 degree temperatures indoors for a few days. close off unused rooms. close doors and vents.
When things are working right, your central air conditioner should run for 15 to 20 minutes and then turn off for a few minutes. It will do this two or three times every hour. It may run longer when it's sweltering outside.
In the summer, experts say the thermostat for your air conditioner should be set to at least 78°F during the day when people are at home. That setting is designed to help people avoid high energy bills in the summer. The lower your thermostat setting, the higher your bill.
You can expect a more considerable maintenance burden if you run the fan continuously, even if you're running the AC fan without cooling. The filter will clog sooner, and the mechanical parts need more frequent attention to avoid breakdowns.
A constantly running fan will increase your utility bills and produce more humidity in your home because it will just blow warm air around without the AC absorbing moisture and heat.
Consequences of Running Your Air Conditioner 24 Hours a Day
Wasted energy: Running the AC to cool your home beyond your comfort level wastes energy and contributes to an increased carbon footprint. This is bad news for the environment and your energy bills.
This means, that in turn, when your setting is turned on auto less electricity is used. When your fan and air conditioner are running all the time, more electricity is produced. All in all, it is better to leave your air conditioner's fan on auto, instead of “On” at all times.
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.
"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.
On an average summer day, a general guideline is that your AC should operate between 12 and 16 hours. However, several factors can influence this, including the outdoor temperature, desired indoor temperature, the size and type of your unit, and your home's energy efficiency.
Allowing your air conditioner to rest is an excellent way to extend its life and ensure it operates efficiently throughout the years. Air conditioners, like homeowners, require rest in order to recover and perform optimally.
Even if you AC is a simple on off system best is to also shut off the compressor and let the fans run for 5-15 minutes until all moist is condensed and evaporated. This will prevent mold from growing in your condenser which will cause the infamous “laundry basket odor”.
Just because the outdoor temperature is above 100, the Ideal temperature to set your AC unit to doesn't change — it's 78 degrees. Higher temperatures in the home are to be expected when the weather is hotter than usual, but your thermostat can still be set the same as if it were a lower temperature outside.
Your AC might not cool properly due to thermostat issues, an undersized unit, or extremely high outdoor temps—so check those first. Keep an eye on airflow—replace clogged filters every 3 months, and make sure vents and ducts aren't blocked for efficient cooling.
Cooling a house from 80 to 72 degrees is a common goal for many, especially during the peak of summer. On average, this process takes roughly two and a half to three and a half hours.
If you wonder, “How long should my HVAC fan run per hour?” then the answer is between ten to 20 minutes for two or three cycles. This works best when your home has a mild outdoor temperature. When temperatures shift strongly towards 0 or 90 degrees (heating or cooling), you will need to run the fan longer.
78°F is generally considered a comfortable temperature for most people in a house, especially in warmer months. It balances comfort and energy efficiency. However, personal preferences and humidity levels can make it feel warmer or cooler, so adjusting slightly up or down may be necessary for optimal comfort.
If you're running your AC fan 24/7, you should probably stop. You'll usually feel cooler if you let the fan turn off between cooling cycles. Why? Because when the AC finishes a cooling cycle, the unit's fan isn't just circulating air.