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Smart Thermostat Not Working
Your smart thermostat has gone offline, has a blank screen, or is not responding to the app.
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What's happening?
Smart thermostats like Nest, Hive, Tado, and Honeywell Evohome connect to your Wi-Fi and allow remote control of your heating. When they stop working, you may lose the ability to control your heating from the app or the thermostat itself may be unresponsive.
What usually causes it?
- Wi-Fi connection lost — router issue or thermostat too far from router
- Thermostat battery dead or charging issue (common with Nest)
- Power supply to the thermostat interrupted
- Software or firmware glitch
- Thermostat receiver or hub offline
- Wiring fault behind the thermostat
Is it dangerous?
A smart thermostat that is not working is not a safety concern. However, if your heating is stuck on or off as a result, you may need to use manual overrides until the thermostat is fixed.
Can I fix it myself?
Restart the thermostat by removing it from the wall plate and refitting it, or holding the reset button. Check your Wi-Fi router is working. For Nest thermostats, charge the battery by connecting it to USB. Check the receiver unit (usually near the boiler) — make sure it has power and the lights are on. Reinstall the app if it is not connecting.
When should you call an electrician?
Call an electrician if the thermostat has no power and you have checked the supply, if the heating does not respond even with manual controls, if the thermostat was recently installed and never worked correctly, or if you suspect a wiring issue behind the unit.
What will the electrician actually do?
- Check the power supply to the thermostat and receiver
- Inspect wiring behind the thermostat for correct connections
- Test the receiver unit and its relay outputs
- Replace the thermostat or receiver if faulty
- Commission and set up the replacement unit
What will it cost to fix?
£60–£200
Wiring checks and simple fixes are at the lower end. If the thermostat unit itself needs replacing, add the cost of the new unit (£100-£250 depending on the brand).
Find an electricianFrequently asked questions
We’re happy to answer all your questions.
Why has my smart thermostat gone offline?
The most common cause is a Wi-Fi issue. Check your router, then check the thermostat and receiver have power. A simple restart often resolves software glitches.
Can I control my heating if the thermostat is offline?
Most systems have a manual override on the receiver unit near the boiler. Look for a switch or button that lets you turn the heating on or off manually.
Do smart thermostats need an electrician to install?
Yes. Smart thermostats connect to your heating system's wiring. Incorrect installation can damage the thermostat or boiler. Always use a qualified electrician for installation.
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