How Low Can You Set Your Thermostat Before a Winter Vacation? Experts Reveal the Safe Limit

Setting the thermostat very low while you're on winter vacation may help you save on bills in the short term, but when you're back home, you may end up paying more than you saved. "Restoring the home's heat is always more energy-consuming because walls and furniture cool off, and it takes hours for them to warm back up before the furnace can actually start warming the air," says Keith Wortsmith, president of DASH Heating & Cooling.

Steady heating doesn’t cause surfaces to cool off and won't create a heavy energy spike when you come back. But what's the ideal temperature to keep your home at while you're away? Our experts break down what to set your thermostat to before you leave, so you can enjoy your vacation without worrying about your energy bill. 

The Best Temperature to Set During Winter Vacation

Leaving the thermostat at 55 degrees Fahrenheit during a winter vacation is a good recommended temperature, says Michael Carson, operations and process automation manager with Service Experts. "This way pipes can’t freeze, and you can quickly reheat your home when you return," he says.

However, if temperatures might drop below freezing while you're away, you may want to consider a bit warmer. "If your area is expecting hard freezes, you need to set your thermostat to 60 degrees," suggests Wortsmith. "In freezing weather, a house inevitably loses heat, and the areas along exterior walls and under sinks where pipes often run, cool off faster than the rest of the house." Additionally, if you live in a home that is exceptionally drafty, Wortsmith says to keep the thermostat between 62 and 65 degrees to compensate for heat loss in poorly insulated areas.

Keeping the heat on, even at a lower temperature, will keep your home warm enough without jacking up your energy bill. "When you return home, set your thermostat back to 68 degrees," says Scott Levene, vice president of Levco. "It won't take too much extra energy to warm up the house to your preferred temperature."

Cons of Setting the Thermostat Too Low

Because the temperature inside wall cavities is always lower than in the living areas, setting it too low is far riskier than setting it too high, experts warn. These are the most common (and costly) consequences that can result from setting a thermostat too low.

• Freezing pipes: Setting the thermostat too low can cause pipes to freeze and potentially burst while traveling. "Even a minor crack can cause a huge leak once everything thaws, releasing hundreds of gallons of water that can cause severe structural damage," Carson says.
• Mold growth: Burst pipes can lead to excess water, potentially causing mold growth. Even without burst pipes, temperatures below 55 degrees can cause humidity fluctuations. "These fluctuations can cause condensation on walls and other surfaces that often causes mold growth," says Wortsmith.
• Danger to pets and plants: If you're leaving pets and houseplants at home during a winter vacation, setting the thermostat too low can be dangerous to them, says Levene.
• System stress: Your home can take hours to reheat once you're back from vacation. "When it takes longer to bring the home back to a comfort zone, that can put stress on the system and spike energy use," Carson says.

Cons of Setting the Thermostat Too High

Although setting the thermostat too high during a winter vacation is less risky than setting it too low, there are still some risks.

• Wasted energy: If you set your thermostat too high, you're wasting energy and unnecessarily increasing your heating bill and energy output.
• Increased wear on the unit: If the thermostat is working unnecessarily hard, it can increase wear on the furnace and blower motor.
• Overly dry air: Higher temperatures can dry out the air, causing damage to wood floors and furniture. 

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Energy-Efficient Tips

Follow this expert advice to keep your home running efficiently—and warmly—in your absence. 

Warm Your Pipes 

Open kitchen and bathroom cabinets to allow warm air to circulate to your pipes to prevent them from freezing, Carson suggests. Also, take the time to insulate any exposed pipes before you leave. "Since your thermostat will be lower, insulation will protect cold water pipes from freezing," Levene says.

Consider a Smart Thermostat

You may want to invest in a smart thermostat so that you can double-check the temperature from your phone, says Matt Gorbacz, owner of Clean Air Technologies.

Check for Drafts

Check for drafts near pipes, windows, and doors. "If you find air coming in, you can use caulk or insulation to block the cold air from getting inside," Carson says. "You can also close blinds to further block out cold air seeping in from windows."

Change the Heat Differential

If you want to save energy without letting your house get too cold, Wortsmith suggests checking your thermostat settings for the heat differential, or swing. "Most thermostats are set really tight—like 0.5 degree—so the furnace turns on as soon as the temperature dips the tiniest bit," he explains. "This results in constant short cycles. If you change that swing to 1.5 or 2 degrees, the furnace will run fewer but longer cycles, which is way more efficient."