Smart Thermostats and Heating Controls: Are They Worth It?

Heating makes up a large share of most household energy use, so controlling it properly matters. Smart thermostats are popular, but they are not a magic fix. This guide explains what they do, what the savings depend on and the basic controls that matter just as much.

The basic controls

Before considering anything smart, check the basics, because many homes have controls that are not used properly.

Programmer or timer: turns heating and hot water on and off at set times.
Room thermostat: switches the heating off when the room reaches a set temperature.
Thermostatic radiator valves (TRVs): control the temperature of individual radiators.
Boiler settings: see our guide to boiler flow temperature.

What a smart thermostat adds

A smart thermostat connects to your Wi-Fi and lets you control the heating from an app. Common features include:

Remote control and easy schedule changes.
Learning or adaptive schedules that start heating earlier to reach the right temperature by a set time (often called optimum start).
Location-based settings (geofencing) that reduce heating when everyone leaves.
Room-by-room control with smart radiator valves.
Usage reports.
Compatibility with weather compensation or modulating boilers.

Do they save money?

Savings depend on how you heat your home now. If you currently heat the house when nobody is in, or have poorly set schedules, a smart thermostat can help. If you already use your controls carefully, the saving may be small. Manufacturers' headline figures often come from favourable comparisons, so treat them with caution. Independent organisations such as the Energy Saving Trust give more cautious estimates.

Compatibility

Check that the thermostat works with your boiler and heating system. Some work with most gas boilers, but others need specific wiring. Combination boilers, system boilers, heat pumps and electric heating can all have special requirements. Ask a Gas Safe registered engineer if you are unsure, as gas boiler wiring should be done by a qualified person.

Smart radiator valves

These let you set different temperatures for each room and schedule them individually. They can be worthwhile in homes where some rooms are rarely used, but they add cost and batteries to maintain.

Sensible ways to use any thermostat

Set a comfortable but not excessive temperature, as a degree lower can reduce use. See what temperature to keep your home.
Do not turn the thermostat up high to heat faster, as it does not work that way.
Use schedules that match your routine.
Keep radiators clear of furniture and bleed them yearly, following our guide.

Heat pumps

Heat pumps work best with steady heating, so large temperature set-backs do not suit them. Follow your installer's advice and use controls designed for heat pumps.

A smart thermostat can be a convenient upgrade, but it is only one part of an efficient heating system, alongside insulation, draught-proofing and a well-maintained boiler.