Common A/C Myths and Misconceptions

Paul Pogue
Written by Paul Pogue
Updated April 13, 2016
Outdoor HVAC fan units
Don't neglect your outdoor fan unit during summer. Keep it clean and clear of obstructions to save energy. (Photo by Summer Galyan)

HVAC experts bust these myths about saving energy during the summer.

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As summer approaches, homeowners’ thoughts turn toward switching on the air conditioning system and cooling off in the hot, sunny days. However, your air conditioner isn’t just a matter of flipping a switch on the thermostat.

“In general, people are very oblivious to their systems,” says Michael McCain, service manager for CARE Heating & Cooling in Lewis Center, Ohio. “It’s out of sight, out of mind. They need preventive maintenance, cleaning and an annual inspection before they turn it on. You wouldn’t abuse your car for years and expect it to keep running without oil changes or air filters.”

Regardless, experts say homeowners often labor under misconceptions about how to get the best A/C performance throughout the summer. Read on for the real deal on some of these myths.

1. There's no need to clean my outdoor unit


The outdoor unit and condenser fan move air through the coils, and it doesn’t take much cottonwood, mud, grass or dirt to get inside and gunk up the works. This decreases your A/C efficiency and spikes your electric bills, but fortunately, cleaning the outdoor unit is an easy DIY job.

“Take a hose and spray down your unit, from the inside on the top and spraying out, so you blow out all the dirt and crap that’s built up,” says Nathan McGuire, regional call center supervisor and quality control analyst for Airtron Heating & Air Conditioning in Indianapolis. 

2. I need to check my air filters frequently


Your HVAC filter serves as the first line of defense against contaminants getting into your HVAC system and clogging up the works, but it needs to be monitored frequently.

“The biggest thing a homeowner can do is make sure they’re religious about changing their filter,” McGuire says. “As the saying goes, ‘Pay your mortgage, check your filter.’ It varies based on system, but you want to check it every 30 days on average, and change it when it’s getting filled up.”

3. I can fix my HVAC unit on my own


Unless you know what you’re doing, you run the risk of an expensive error once you start getting into the nuts and bolts of the system.

“A capacitor might be $6 online and you’ll think you can install it yourself, but the cost is going to be substantially more if you connect the wrong wire and fry something else,” McGuire says. “Leave it to the professionals.”

4. I should leave my thermostat fan setting on "auto"


This is a wise move during winter, but during the summer, running your HVAC fan all the time, even when the A/C isn’t operating, actually saves energy and improves comfort in the long run.

“It keeps air moving throughout the house and balances things so it’s not as hot upstairs while it’s cooler downstairs,” McCain says. 

5. I should set my thermostat to a higher temperature while I'm away during the day


Instead, you should find the temperature you’re comfortable with and leave the thermostat there.

“People think they can set the temperature high during the day and then turn it down when they get home from work, but that’s not effective,” McCain says. “They expect the system to catch up, but it doesn’t. If you’ve let it get hotter during the day, it’s a lot of load for the system to overcome before it can start cooling the house and removing humidity.”

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