What temperature should I leave my house at in winter when I am away?
Leave the heat on and set it no lower than 55°F; that is the American Red Cross recommendation for going away in cold weather. The thermostat only tells you about the room it is in, though. Pipes in a garage, crawlspace, or exterior wall can be much colder, and the setting does nothing if the furnace or the power fails, so someone or something needs to be watching.
Why 55°F and not lower
The house loses heat toward its edges. With the living space at 55°F, pipes in exterior walls and unheated areas still have some margin above freezing. Set it to 45°F and that margin is gone on a very cold, windy night.
Open the cabinet doors under kitchen and bathroom sinks before you leave so warmer room air reaches the plumbing, and keep the garage door closed if there are water lines in the garage.
The setting does not help if the heat stops
A tripped furnace, an empty propane or oil tank, or a power cut lets the house cool toward the outdoor temperature no matter what the thermostat says.
Put a temperature sensor where the pipes are, alert at 38–40°F so there is time for someone to get there, and make sure a second person receives the alert. An alert that fires when the sensor stops reporting covers power and internet outages.
For a long absence
If a house will sit empty for weeks, shutting off the water at the main and draining the lines removes most of the risk; a plumber can winterize it properly. Keep the heat on anyway to protect the building and anything that cannot be drained.
Frequently asked questions
Is 50°F warm enough to keep pipes from freezing?
Often, but it leaves less margin than the 55°F the American Red Cross recommends. The colder the climate and the more plumbing you have in exterior walls or unheated spaces, the more that margin matters.
Should I turn the heat off to save money while away?
No, not in freezing weather. The Red Cross advice is to leave the heat on; a burst pipe costs far more than the heating bill.
Related
- How can I monitor the temperature in a cabin remotely?
- What temperature should a freeze alarm be set to?
- Freeze season checklist
Sources
Get a freeze alert for your space
ProbeHarbor watches probes in garages, crawlspaces, and cabins and alerts you before pipes freeze. The free plan includes email alerts; bring an ESP32 probe or connect Home Assistant.