What is the payback period of a smart thermostat?

Manufacturers claim that thanks to their smart thermostats, your heating system will only be active when needed. In this way, you should be able to reach significant savings on your energy bill. The question is, are these savings worth investing in a smart or Wi-Fi thermostat?

More and more people are discovering how easy it is to operate the heater with a smartphone or tablet. Whether a smart thermostat will save you money depends on whether you take advantage of its ability to intelligently control the heating.

In most households, the largest part of the energy bill is caused by the home heating and hot water system. The best way to save energy is to turn off these systems when you are asleep or absent. Of course, you only want the system to be active when needed, with some variation in the schedule, so your house can reach the desired temperature just when you need it. Programming your schedule is only possible with a connected smart thermostat or a programmable thermostat without WiFi connection. Smart thermostats are characterized additionally by using an app, which makes it easy for you to program your heating schedule, wherever and whenever you want.

On top of that, you can save even more energy with a learning thermostat. This means the thermostat is able to get to know your heating system and your house and can predict when to start heating your home to make it comfortable when you need it to be.

Finally, a big advantage of a smart thermostat is that it can be controlled remotely, even when you are not at home. How many times have you forgotten to switch off the heating when you left home? With the app on your phone, that's easy to correct.

The amount of money you can save with any smart wireless thermostat depends mostly on how you use it. Your monthly heating costs depend heavily on the weather, your home, the number of people in your household, and your personal preferences. All smart thermostat manufacturers try to make their devices as energy-efficient as possible without sacrificing comfort. With so many factors, it’s hard to give an exact answer.

One reason for wasted energy can be a single-zone, or centralised, heating system – and it’s probably the most common setup! This means you have one thermostat and one set temperature for the whole house. For example, if your thermostat is set to 20°, your boiler shuts off when the living room reaches 20°, even if the temperature in the upstairs bathroom is only 15°. To warm the bathroom, you’ll need to increase the temperature in the living room.

If this is a problem you recognise, you might be happiest with a thermostat that supports multiple zones with radiator valves. Systems like the Honeywell Evohome and Tado communicate with each radiator independently and adjust the temperature only where  needed.

If you don’t need to control individual radiators, you might want a thermostat with more features, like the Nest Learning Thermostat. The Nest learns your habits and lifestyle and adapts its programming accordingly. It senses when someone is in the room and displays time and weather information. It provides usage statistics, lets you know in real-time when you’re saving energy, and integrates seamlessly with other Nest products. The Nest also has a feature that lets you get the most out of a heat pump if you have that instead of a boiler.

How much energy a smart thermostat can save largely depends on how you use the device. About 60% of our energy bill goes to heating, sometimes even more. The average consumption of a household is 3,000 m3 of gas per year. With gas prices (including all legal fees) of around 40 pence per cubic meter, your heating costs £1,200 a year.

This means that if you:

• save 10% energy, you save £120

• save 20% energy, you save £240

• save 30% energy, you save £360

If you do not program or use your thermostat cleverly, you will not save energy. While many people already try to use their heating efficiently, by consistently using your smart thermostat you can still make some decent savings. The above calculation shows that every percent of reduction yields a lot of money. This shows the investment in a new thermostat is recouped quickly.

How much money you can actually save with a smart thermostat, can be estimated by analysing your current heating profile and asking yourself these questions:

• Have I already set up a heating schedule program? Or do I find that too much of a hassle?

• Did I ever reprogram a thermostat after a power outage?

• Do I really only heat my house when I'm there?

• How warm do I turn my heater? Do I heat it often above 25 degrees Celsius, or do I pull on a sweater?

• If it is cold in the winter, do I turn off the heating, or do I leave it at about 15 degrees Celsius, so my house does not cool down too much?

• Do I forget to turn off my heating occasionally?

Most smart thermostats keep their heating program during a power outage, so you don't have to reprogram it. You can also easily temporarily override a set program as you wish. The thermostat then automatically picks up, or resumes, the set program in accordance with the set time.

Many smart thermostats use an open communication protocol like IFTTT (If This Then That). This means that they can be easily connected to other smart devices. For example, you can automatically turn off the heater at a low noise level (which may indicate absence). Also, you can connect the thermostat to an outdoor temperature sensor. If it gets warmer or colder, the thermostat can adjust accordingly.

In other words, a smart thermostat is more worry-free and convenient and gives you a more accurate temperature control. And by doing so, it can help you save some serious energy and money.