What temperature should a freeze alarm be set to?

Well above freezing: high enough to give someone time to get there before pipes are at risk.

Will a smart thermostat do the job?

Some send alerts, but they share the furnace's power and Wi-Fi. A separate battery sensor is a useful backup.

Where do leak sensors go?

On the floor at the water heater, under sinks, behind the washer and under the house where pipes run.

WW-1Winter watch

Freeze alarms and remote checks

A freeze alarm for a vacation home is a temperature sensor that sends a text or call when the house gets cold, paired with leak sensors at the water heater and under sinks; it only helps if someone local can get to the house quickly when it alerts.

Time: An afternoon to set upWho: YouWhen: Winter, set up at closing

By the Shore House Pipes editors · sources checked October 31, 2026 · how this manual is written

Round leak sensor on the floor beside a water heater pan, a small sensor on a shelf. AI-generated picture.

Bring

A temperature sensor with alerts (Wi-Fi, cellular or landline types exist)
Two to four leak sensors
A local person with a key and your plumber's details

The procedure

Pick how it reports. Wi-Fi sensors stop reporting when the internet or power goes out. Cellular or battery-backed units keep working longer. Choose for the house, not the brand.
Set the alert temperature. Set it well above freezing, so there is time for someone to get there before the pipes are at risk.
Place the temperature sensor. Put it in the coldest room with plumbing, not beside the thermostat.
Place leak sensors. At the water heater pan, under the kitchen sink, behind the washer and on the floor of the space under the house if pipes run there.
Name a responder. Give a neighbor or house-watch service a key, the main valve location and your plumber's details.
Test it. Trigger each sensor before you leave and confirm the alert reaches you and the responder.

Why does a freeze alarm need a power-outage plan?

Winter storms knock out power, which stops the heat and often the internet. A sensor that goes quiet at the same moment the furnace stops tells you nothing. Battery backup and a cellular link close that gap.

Do leak sensors stop water?

No. They only warn you. To stop water automatically you need a shutoff valve on the main, covered in WW-2.

The numbers behind it

Figure	What it means	Source
Above 55°F	the heat setting the alarm is guarding	Arlington County Emergency Management

Questions owners ask

What temperature should a freeze alarm be set to?: Well above freezing: high enough to give someone time to get there before pipes are at risk.
Will a smart thermostat do the job?: Some send alerts, but they share the furnace's power and Wi-Fi. A separate battery sensor is a useful backup.
Where do leak sensors go?: On the floor at the water heater, under sinks, behind the washer and under the house where pipes run.

Sources for this procedure

Each source was opened and the cited figure or sentence checked on October 31, 2026. Steps marked PRO are described, not taught: they belong to a licensed plumber or the utility.