You should set your thermostat no lower than 55°F to prevent cold weather damage to your home. Adjust up based on your home’s climate and insulation to ensure safe indoor temperatures.
Whether you’re going on vacation and want to adjust your thermostat while you’re away, or interested in saving on your energy bill all winter long, here’s what you need to know.
The difference between personal comfort and safety
For this discussion, we are not focusing on optimal comfort. If you’re heading out of town, you won’t be there to be sad because it’s 10 degrees colder than normal. And if you’re staying indoors, we assume you’re prepared for the coolness and have a cozy blanket ready.
Also, things like preferred winter temperatures are subjective and opinions vary widely. While my immediate family loves to keep the house cool in the winter, our relatives in semi-tropical climates think we’re crazy for setting our thermostat so cold.
However, if you’re curious about the commonly accepted optimal thermostat range for colder climates, keeping around 68-72°F is a sweet spot for most people’s overall comfort.
But overall comfort is not the same as how far you can safely turn your thermostat without risking harm to yourself or the physical structure of your home.
As a general rule of thumb, the recommendation is to keep your thermostat set to at least 55°F. That’s well above freezing and ensures that even if it’s a little chilly in your home, enough warm air is circulating around your home to keep you out of the danger zone.
If setting your thermostat to 55°F isn’t keeping your home sufficiently and evenly warm because outside temperatures or poor insulation are causing the thermostat reading to be inaccurate throughout your home space, adjust your thermostat upwards accordingly.
Monitor your home while you experience
If you plan on dialing back your thermostat, we highly recommend that you do a few simple things to ensure your experiment runs smoothly.
First, play around with the temperature when you’ll be home for an extended period during cold weather. Your first attempt to turn your thermostat down much lower than normal shouldn’t be right before a two-week winter break.
Second, actively monitor your home during the process, including less used or infrequently accessed spaces. Because it’s hard to measure actual temperature and humidity (and because you can’t be everywhere at once), it’s worth buying a bundle of inexpensive Bluetooth thermometer/hygrometer units. You can rotate them through locations in your home to see how cold/wet it gets in your basement, attic, basement, and other spaces during your experiment.
In addition to pipes in crawl spaces and the like, if you have pipes on exterior walls (like a kitchen sink against an exterior wall), be sure to pay attention to things like how cold it gets inside the enclosed cabinet where the pipes are. .
You may not feel uncomfortable when you dial back the thermostat, and the pipes may not be at risk of freezing, but there can be side effects that you may not have anticipated.
For example, let’s say that previously enough heat seeped through your home’s poorly insulated floor into the crawlspace below the floor to keep moisture and mold at bay. But then, after adjusting the thermostat a lot, less heat gets in and the humidity level in the mezzanine increases, resulting in slow but eventual damage to the wood structure of your home.
You may end up remedying that problem not by turning up the thermostat again, but by steam sealing the crawlspace, installing a dehumidifier, or some other solution. But you want to be aware of this and any other changes in your home that result from changing your heating and cooling routine.
While every home is different, here is a brief summary of some common things to watch out for:
- Overall humidity level: People in a house who simply live there, in addition to cooking, showering and other daily activities, increase the humidity. If your home is damp but cold, moisture will condense on cold walls and cause mold and mildew problems.
- overall air quality: If you have forced air heat, reheat causes the oven fan to run less often. You may want to set your thermostat to run the fan on a schedule to circulate the air.
- Cracks in drywall or plaster: A classic trope of abandoned houses in movies is crumbling walls and missing plaster patches. That’s not so much a movie trope as it is a harsh reality. Extreme temperature changes can lead to significant expansion and contraction of building materials. Keeping your home at a stable, human-friendly temperature is not only good for you, but also for the structure itself.
- ErasersNote: Dialing the thermostat back won’t cause drafts, you’ll just notice them more. Sealing them is a good practice in general, but it is very useful if you use the oven less. You want to keep all the heat inside.
We’re not sharing these things to scare you into never lowering your thermostat again, but simply to inform you of things to consider when significantly adjusting the temperature in your home outside of the range you’ve previously kept it within.
As long as you monitor the temperature in your home and make adjustments to make sure no part of it gets too cold, you can safely lower your thermostat.