Auto or Off Fan Setting – Which is Better for Your AC System & Furnace?

There’s a popular myth about the “fan on” setting on a thermostat. And that is, some people think it means that instead of blowing cool air, your system will suddenly start acting like a window or floor fan and simply circulate indoor air, regardless of its temperature or humidity level.

Wrong!

The “on” setting is simply another way – besides “auto” – to heat and cool your home. Let’s look at what each setting does along with their advantages and disadvantages.

Fan “Auto” Setting

In the “auto” position on your thermostat, the fan turns on only when warmer or cooler air is required. Your system will eventually reach the pre-set level – when it does, the system’s fan will shut off until the cycle is repeated.

Advantages

• Better temperature control
• Better humidity control
• HVAC filters don’t need to be replaced as often
• Lower monthly energy bills and greater energy savings

Disadvantages

• Can result in hot and cold spots since cool air isn’t evenly distributed throughout the home
• More wear and tear on the fan because it’s frequently starting and stopping
• May result in poorer indoor air quality

Fan “On” Setting

Here, the fan is constantly on while your heating or cooling system is running. If it is excessively hot and humid in the summer or frigidly cold in the winter, you’ll want to leave the fan in the “on” vs. “auto” position.

Advantages

• Cleaner indoor air since air is always moving through your home’s air filtration system
• Extended fan lifespan due to fewer start and stop cycles
• Fewer hot and cold spots as cool air is evenly distributed into all rooms

Disadvantages

• The fan is cooling your home long after the desired indoor temp is reached, resulting in higher utility costs and wasted energy
• More frequent filter replacement
• Higher risk of premature equipment failure.

Which setting is right for your household? Well, if you’re generally not bothered by the summer heat, choose the “auto” setting. It’s also your best bet if you’re looking to reduce utility bills (and who isn’t?). On the other hand, homes with elderly relatives or those who suffer from allergies or asthma will enjoy greater comfort and safety with an AC system or furnace in the fan “on” position.

Would you like to know more?  Contact Correct Temp today. At your request, we’d be happy to visit your home and provide a free estimate on a new heating or AC system.