Best for freeze alerts in thermostats and freeze alerts
Our pick for freeze warnings: a smart thermostat that can alert your phone when the house gets too cold, with a power kit in the box for homes without a C wire.
Our score: 8.5/10 out of 10Researched, not lab-tested
- C wire
- Needed; adapter kit in the box
- Warranty
- 3 years
Is it right for you?
Pros
- Low-temperature alert can flag a furnace failure before pipes freeze
- Power Extender Kit included for homes without a C wire
- Works with most 24 V systems, including heat pumps with aux heat
- ENERGY STAR certified; dual-band Wi-Fi
- Three-year warranty, five when installed by a pro
Cons
- Alerts need Wi-Fi and internet up at the time
- Runs only 24 VAC equipment, not line-voltage baseboard heaters
- Alert threshold range isn't published for this model
- Room sensors and security features cost extra
- Best for
- Homes with a 24 V furnace, boiler or heat pump where an owner wants a phone alert if the heat fails while they are away in winter.
- Not for
- Electric baseboard (line-voltage) heating, or homes without reliable Wi-Fi.
Our verdict
A smart thermostat is cheap freeze insurance for a home that sits empty in winter, and ecobee’s Enhanced model is the one we’d pick for it. Under Reminders & Alerts, on the thermostat or in the app, you can set a low-temperature alert, which ecobee says can warn you of a furnace problem before your pipes freeze; the app also flags unexpected temperature or humidity changes.
It runs on 24 VAC through the C and Rc terminals, and the included Power Extender Kit lets it run in most homes without a C wire. ecobee lists support for most 24 V systems: furnaces and air conditioners up to two stages, heat pumps with one aux stage, boilers, and some fan coils, plus one accessory such as a humidifier. Line-voltage baseboards are out. It is ENERGY STAR certified, with a three-year warranty (five when a pro installs it), and ecobee sells it on its Canadian store too. The Google Nest Thermostat is the lower-cost alternative in our thermostat comparison.
What it can and can’t do in a freeze
Set the alert before winter and switch on notifications in the app so it reaches your phone. Like any Wi-Fi thermostat, it needs power and a working furnace or boiler to heat, and Wi-Fi with internet to reach your phone. In a power cut that takes out the heating and the router, it can’t heat or warn you, so plan for that separately: our guide on keeping pipes from freezing in an outage covers it.
Room SmartSensors (sold separately) add temperature readings from other rooms; ecobee’s door and window sensors need its Smart Security subscription for open-window alerts.
Specs
ecobee Smart Thermostat Enhanced (EB-STATE6L-01)
Freeze alerts
| Low-temperature alert | Yes |
|---|---|
| How it warns | Low-temperature alert in the ecobee app |
| C wire | Needed; adapter kit in the box |
| Works with | Most 24 VAC systems: 2H/2C, heat pumps 2H/2C + aux, boilers |
Other details
| App control | Yes |
|---|---|
| ENERGY STAR | Yes |
| Warranty | 3 years |
Maker’s figures, checked 3 Nov 2026.
ecobee Smart Thermostat Enhanced questions
Can an ecobee thermostat warn me before my pipes freeze?
Yes. Set a low-temperature alert under Reminders & Alerts, in the ecobee app or on the thermostat. ecobee says this can tell you about a furnace problem before your pipes freeze. Turn on notifications so the alert reaches your phone.
Does the ecobee Enhanced need a C wire?
It runs on 24 VAC through the C and Rc terminals, but the Power Extender Kit in the box lets it work in most homes without a C wire.
Will the alert work during a power outage?
Only if the thermostat, the router and the internet connection all still have power. In a full outage it can’t send an alert, and the heating usually can’t run either.