How do smart thermostats work?

Smart thermostats are one of the most popular devices you can buy if you’re building a connected home. They should not be confused with smart meters, which digitally send meter readings to your energy supplier. They let you remotely control your home’s temperature via a tablet, smartphone or desktop for greater control over your central heating.

In a traditional non-digital thermostat, you set the temperature on a dial. A thermometer inside the thermostat is connected to metal strip. This strip completes an electrical circuit, that tells your boiler to turn on. As your home heats up, the strip does too. When it gets to the desired temperature, the circuit breaks, as the metal strip has expanded, and moves away from its connectors. The boiler then turns off. When the house cools, the strip does too and clicks back into place making the circuit complete, and the boiler turns on again.

With digital thermostats, the circuit is controlled by a thermometer that shuts off the boiler automatically when the desired temperature is reached.

Smart thermostats are more intelligent and connect both to your boiler – via your existing thermostat wired connection – and your home Wi-Fi network. This means that your old boiler can be part of the smart home, without needing to buy a new boiler with embedded Wi-Fi. Of course, your boiler needs to be compatible – check carefully when you are choosing your smart thermostat solution!

Now, with the simple download of a companion app, you can alter your thermostat settings from wherever you are in the world at the tap of a screen. Some even connect to your air-con too!

So for many smart thermostats, to change the temperature of the home while you’re out, you would:

  1. Open the smartphone app and set the temperature
  2. The new setting is sent via the Internet to your home
  3. Your Wi-Fi router transmits the instruction to your thermostat
  4. Your smart thermostat readjusts the temperature and sends a signal to your boiler to turn on or off

Smart thermostats also come with a range of features that hopefully will help lower your energy bill. They can learn your behavior and make sure that your home isn’t heated when you’re not in the house. And if you worry that you’ve gone on holiday, and left the heating on, one quick check on the app will let you know, and you’ll be able to turn off the heating if so.

There are many smart thermostats on the market, and your energy supplier might be able to give you a good deal on one too, so shop around and don’t forget to check out the reviews.

If you do get a smart thermostat, make sure you take the appropriate security precautions, for example by choosing a secure password, or someone could take control of your thermostat if not. You might find they turn up your heating when you’re away, causing you a very high bill.