In short
It can be, if you will actually use the scheduling, remote control and room-by-room features. A smart thermostat does not make heat by itself; it helps you avoid heating an empty home. The Energy Saving Trust says savings depend on how you use it. Check it is compatible with your boiler first.
What does a smart thermostat do?
A smart thermostat does everything a normal programmer and room thermostat do, plus it connects to the internet. Depending on the model, it can let you control the heating from your phone, learn your routine, switch off when everyone has gone out, and, on some systems, talk to the boiler to adjust how hot it runs.
When is it worth it?
- Your hours vary, so a fixed timer often heats an empty house.
- You want to turn the heating on or off on the way home.
- You want different temperatures in different rooms, using smart radiator valves.
- You have a combi and want the boiler to modulate more smoothly, using a control that supports load or weather compensation.
When is it less useful?
- Someone is home most of the day and the heating pattern rarely changes.
- You will not use the app or set up the schedule.
- Your existing programmer, room thermostat and TRVs already work well and you use them properly.
The Energy Saving Trust points out that smart controls can save energy, but they can also increase use if they make it easier to heat more often. The thermostat setting itself matters most: it suggests the lowest comfortable temperature, which for most people is between 18°C and 21°C.
Do the regulations require one?
Not on its own. In England, Approved Document L says a new combi boiler in an existing home should come with at least one of four measures: flue gas heat recovery, weather compensation, load compensation, or a smart thermostat with automation and optimisation. Your installer chooses the one that suits your system. See our new boiler regulations guide.
Will it work with my boiler?
Most smart thermostats work with standard combi and system boilers, but wiring and boiler communication differ. Some boilers use their own brand's controls or a particular protocol for modulating control. Check the thermostat maker's compatibility list for your boiler model, and whether it controls hot water too if you have a cylinder.
What CombiCert would check
We check which controls you already have, whether the boiler supports OpenTherm or a simple boiler-plus-thermostat setup, and whether a smart thermostat will actually help how you heat the house. If you want one fitted with a new boiler or on its own, we quote it as a clear line on the estimate.
When to call a Gas Safe engineer
Swapping a battery room thermostat is simple, but wiring a new control into the boiler or wiring centre means working on mains electrics and the boiler's control connections. If you are not sure, get a heating engineer to fit it. Never remove the boiler case yourself. Our heating controls questions cover programmers, TRVs and zones.
Need a hand? CombiCert in Telford
CombiCert Ltd is a Gas Safe registered (621146) gas and heating company based at The Old School House, Park Lane, Telford TF3 4TG, working across Telford and Shropshire for homes and businesses. We are open Monday to Saturday, 08:00 to 19:45 (closed Sunday).
Boiler repairs and services from £90 + VAT. New boilers from £1,750 inc VAT, subject to a site inspection; thermostats are a paid extra.
See Central heating engineer in Telford, or call or WhatsApp 07393 220694, or email hello@combicert.co.uk.
We cover Telford and nearby, including Wellington, Madeley, Dawley, Oakengates, Shifnal, Newport, Ironbridge and Shrewsbury.
Sources
Frequently asked questions
Will a smart thermostat save me money?
It can, if it stops you heating the home when nobody is in or lets you set lower temperatures in rooms you do not use. The Energy Saving Trust says savings depend on how you use it, and that easier control can also lead to heating more often. Set the lowest comfortable temperature and a realistic schedule.
Does a new combi boiler need a smart thermostat?
Not necessarily. Approved Document L says a new gas combi in an existing home in England should have at least one of four measures: flue gas heat recovery, weather compensation, load compensation, or a smart thermostat with automation and optimisation. Your installer picks the measure that suits your system.
Can I fit a smart thermostat myself?
Some battery or plug-in models are designed for simple swaps, but many need wiring into the boiler or wiring centre at mains voltage. If you are not confident with electrics, have a heating engineer fit it. Never open the boiler case: anything inside it is work for a Gas Safe registered engineer.
What is the difference between a smart thermostat and smart radiator valves?
A smart thermostat controls when the boiler runs and the temperature in the room where it sits. Smart radiator valves control each radiator separately, so you can heat rooms at different times and temperatures. Used together, they give room-by-room control, but they cost more than a single thermostat.
This answer is general information, not a substitute for an on-site assessment by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.