How HVAC Pros Say To Set Your Thermostat When Temperatures Drop Below Freezing

Even though Winter Storm Fern has tapered off, frigid temperatures continue to linger in many parts of the country—not just where the snow fell.

In parts of the northern Plains and Great Lakes states, near or below zero temps and wind chills are expected.

The National Weather Forecast even predicts wind chills of -10 in the Dallas area.

Regardless of where you live, you might be wondering how to set your thermostat during this arctic weather. 

After all, it can be difficult to balance comfort and energy efficiency in your home while still preventing frozen pipes or strain on your system.

The answer depends on your situation but most HVAC experts agree that 68 F is the sweet spot.

How to set your thermostat 

During below-freezing weather, David Watkins, CEO of Watkins Heating & Cooling in Dayton, OH, directs homeowners to Energy Star’s guidance—set the thermostat as low as comfortably possible. 

“This is typically around 68°F while awake and at home, then about 3 to 8 degrees lower when sleeping or away—usually around 65°F,” explains Watkins.

Ultimately, however, Watkins believes you should turn your thermostat to whatever you consider comfortable and understand the cost tradeoff. 

“As a rule of thumb, raising the thermostat by 1 degree throughout winter can increase heating costs by around 3 to 5 percent, which translates to roughly $50 to $100 over the course of a winter season,” says Watkins.

TJ Laury, president at Ben’s ProServ in Vineland, NJ, agrees with Watkins on the 68 F number but recommends you lower your thermostat more dramatically if you’re going to be away for several days. 

“Whatever you do, however, make sure it never dips below 55 F, or your pipes might freeze,” says Laury.

Dan Cronen, HVAC Expert at SupplyHouse.com, believes there’s no magic number for your thermostat. He suggests you ignore the number and ask yourself, “Am I comfortable?” If the answer is, “No, I’m cold”, turn it up! If the answer is, “No, I’m hot”, turn it down. 

If you are comfortable, forget about it and let the thermostat do its job. 

Just keep in mind that if it’s really cold out, your system is going to have to work harder to keep you comfortable and that means it will run more and cost more— that’s just basic physics. 

“The only way to save is to turn the heat down at the cost of your comfort. It comes down to your personal comfort versus cold tolerance, because there’s no cheating physics,” explains Cronen.

Winter HVAC maintenance tips from the pros

There are a number of steps you can take to keep your HVAC system efficient and functional this winter and beyond. Here’s what the pros recommend:

Consider HVAC zoning

HVAC zoning allows different areas of the home to be heated independently.

“By only heating occupied spaces, you can reduce energy waste and improve overall comfort,” says Michael Morey, digital product management leader at Trane in Houston.

Change filters

According to Laury, a clean filter is an effective yet ridiculously easy way to keep your HVAC system in good condition. Old crusty ones can slow down your heat or cause it to shut down altogether. 

“Change your air filter every 30 to 90 days,” explains Laury. 

Seal drafts

Sealing drafts around windows and doors is another major opportunity in winter, as these cold air leaks force a heating system to run longer.

“Drafts also leak humidity, making homes feel even colder and drier than the thermostat temperature,” explains Watkins.

Freezing, windy weather is often the best time to identify drafts, because you can feel them in places you might never notice when it’s warm outside.

Schedule an HVAC tune-up

Ask an HVAC pro to come to your home and test your system—ideally before the freezing temps hit. They may be able to spot issues that are invisible to the naked eye and offer recommendations for repairs before more expensive ones are needed.