A heating-only swap costs about £150 fitted, and smart thermostat installation cost reaches £450 or more once you add smart radiator valves in several rooms. The thermostat is only part of the price. A receiver, wiring changes and the number of rooms you control move the total as much as the brand does. Our smart thermostat installation page explains the work in detail.
Smart thermostat installation cost by job size
Typical UK smart thermostat installation costs, supplied and fitted
| Job size | What it usually covers | Typical cost |
|---|---|---|
| Small | Heating-only smart thermostat replacing a wired one, supplied and fitted | £150–£250 |
| Typical | Heating and hot water control, with a receiver and some rewiring | £250–£330 |
| Large | Smart thermostat plus smart radiator valves in several rooms | £330–£450+ |
Whole-house control with a smart valve on every radiator can cost more than the top of this range, depending on how many rooms you have.
What you pay for with a smart thermostat
- The thermostat unit, which is the part you see and use
- A receiver that switches the boiler on and off, wired in or plugged in
- Labour to remove the old controls and wire the new ones
- Setting up the app, the schedule and the hot water program
- Testing the boiler responds as it should
- Smart radiator valves, if you want room-by-room control
What changes smart thermostat installation cost
- Wired or wireless. A like-for-like wired swap is cheaper than running a new cable.
- Hot water. Controlling a cylinder as well as the heating needs extra wiring and a second channel.
- Boiler compatibility. Some units use a modulating control that needs a compatible boiler, and others only switch on and off.
- Number of rooms. Each smart radiator valve is an extra item to buy, fit and set up.
- Position. A new thermostat in a new location needs cable, and may need a hole through a wall.
- Where the receiver goes. If it is wired inside the boiler casing, many manufacturers prefer a Gas Safe engineer to do it.
Buying the thermostat yourself and finding it does not suit your boiler is a common reason for a wasted call-out. Ask the installer to confirm it works with your boiler and wiring before you pay.
Will a smart thermostat save money?
Savings depend on how you heat the home now. A thermostat that stops the boiler heating an empty house can help, but it will not fix a system that heats badly. If radiators are cold at the bottom or the boiler is old, start with the circuit. The central heating problems explained guide helps you see what is wrong, and a heating system upgrade often includes new controls anyway.
DIY or professional fitting?
Many smart thermostats are designed for simple fitting, but the wiring varies between homes. If your existing thermostat is a plug-in type or battery powered, it is a small job. If wiring sits inside the boiler, or the house has zone valves, a professional is safer. Check any engineer who works on the boiler on the Gas Safe Register, and add up the whole budget with the heating cost calculator.
Frequently asked questions
How much does smart thermostat installation cost?
As a guide, a heating-only unit is about £150 to £250 fitted, with hot water control about £250 to £330, and smart radiator valves in several rooms up to £450 or more.
Will a smart thermostat work with my boiler?
Most do, but it depends on the boiler and the wiring. Ask the installer to check, or check the maker's compatibility list before you buy.
Do I need a Gas Safe engineer to fit a smart thermostat?
Not usually, as fitting a thermostat is wiring rather than gas work. If the receiver must be wired inside the boiler casing, a Gas Safe engineer is often preferred.
Will a smart thermostat lower my heating bills?
It can, if it stops you heating at the wrong times. How much depends on your habits and on the condition of the heating system.
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