Most thermostat’s have a fan setting with two options: On and auto. But many homeowners don’t even know what the difference is or why they should care.
Oh, but you should care—money is on the line, people!
Let’s go into the difference between these two settings and explain why you should never leave the setting on ON (say that 3 times fast).
The difference between ON and AUTO
This setting controls the AC and furnace’s blower, which distributes air throughout your home.
ON mean the blower is on 24/7, regardless of whether the air is being heated or cooled or not.
AUTO means that the blower runs ONLY when the AC or furnace is cooling and heating the air respectively.
So which setting can drain your bank account? Read on.
Why ON is bad news for your bank account
Since ON keeps the blower on 24/7, it can cause a few costly problems.
Drives up electric bill: Since the blower never stops, it’s constantly using electricity.
Lowers equipment lifespan: The blower is bound to break down sooner rather than later since it’s always on.
Worsens air leakage in the home: According to ENERGY STAR, the typical home loses 20% to 30% of the air flowing through the duct system. (Imagine losing almost a 1/3 of the gas you put in your gas tank!)
If you have duct leaks outside the building envelope (aka, the crawl space or attic), then leaving the blower on can increase infiltration (unconditioned air getting in) and exfiltration (air leaking out). In both cases, your home takes longer to heat and cool off, leaving you uncomfortable.
Increases humidity level in your home summer: Your AC has 2 jobs: cool your air and dehumidify your home. Because of the latter, water condenses on the AC’s evaporator coil (the part that cools the air).
By leaving the fan blowing after the AC shuts off, the blower will blow air over that wet coil, distributing humidity back into your home—leaving you sticky and uncomfortable during the cooling seasons.
Want to learn other ways to keep your energy bills low?
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