A smart thermostat replaces a conventional programmer and room thermostat with a system you can control via an app, set to respond to your occupancy patterns, and integrate with other smart home devices. The energy savings headline figures (manufacturers claim 10–30%) are real but highly variable — a household that already heats efficiently gains less than one that historically heats poorly scheduled rooms. The value of smart thermostats is as much about convenience and control as raw bill reduction.
Main Systems Compared
Google Nest Learning Thermostat learns your schedule automatically over the first week of use, adjusting based on when rooms are occupied. It's well-designed hardware, integrates with Google Home, and works as a single-zone system or with room sensors. The main limitation is that it requires a C-wire (common wire) from your boiler system — some older UK installations lack this, requiring an adapter or additional wiring.
Hive Active Heating (British Gas) uses a wireless hub and separate smart thermostat. Installation is typically done by a British Gas engineer. It supports multi-zone heating with smart TRVs on individual radiators. It's one of the most installer-familiar systems in the UK, which means professional support is readily available.
tado specialises in multi-zone control with room-by-room smart TRVs. Its geofencing (using your phone's location to begin heating before you arrive) is more reliable than many competitors. tado also now has heat pump optimisation modes, making it a strong choice for homes transitioning to heat pumps.
Honeywell Home (Resideo) thermostats are widely installed by heating engineers and plumbers as standard. The T6 and T9 models are solid, reliable, and less fashionable — which also means more plumbers know how to install and configure them correctly.
Multi-Zone Heating
A single thermostat controls the whole house from one room. Multi-zone systems — using smart TRVs on each radiator — allow different temperatures in different rooms simultaneously and avoid heating unoccupied rooms. For a house with distinct occupancy patterns (home office, children's bedrooms, rarely used guest rooms), multi-zone delivers the largest savings.
Heat Pump Compatibility
Heat pumps operate differently from gas boilers — they work best running at low, constant temperatures rather than the on/off cycling that suits gas. Not all smart thermostats are optimised for this. tado, Nest, and some Honeywell models now have heat pump modes that adjust control logic accordingly. If you're planning a heat pump, check heat pump compatibility explicitly before purchasing a thermostat system.
Costs
| System | Hardware cost | Installation |
|---|---|---|
| Nest Learning Thermostat | £200–£250 | DIY or £80–£150 |
| Hive Active Heating | £150–£200 | Included with BG install |
| tado (thermostat + 5 TRVs) | £350–£500 | £100–£200 |