Last updated: 19 July 2026 · Originally published March 2026 · By James Wright
Last checked: 19 July 2026. This is an evidence guide, not a promise that a device will pay for itself.
| Category | What it can change | Evidence needed for a saving claim | Important UK check |
|---|---|---|---|
| Heating controls | Schedules, set-points and zoning | Measured heating kWh before/after | Exact boiler, hot-water and wiring compatibility |
| Smart radiator valves | Room-by-room heat demand | Room use and measured heating consumption | Valve fitting, compatible hub and call-for-heat path |
| Smart plugs | Selected appliance runtime and standby | Plug-level kWh measurement | Maximum load; never use with an unsuitable appliance |
| LED smart lighting | Lamp wattage and on-time | Old versus new watts × measured hours | B22/E27/GU10 fitting and safe switch/dimmer setup |
| Energy monitors | Visibility rather than automatic saving | Verified baseline and behaviour change | Meter/service compatibility and data access |
Calculate, do not promise
Use measured kWh and the household’s tariff. Do not use the whole price cap as the heating bill, include standing charges as avoidable, or add overlapping manufacturer percentages together.
See transparent calculation examples. None of these categories guarantees a cash saving.
Smart Home UK Team - Research-led UK smart-home editors who compare manufacturer specifications, UK availability, verified owner feedback and authoritative sources. Independent. No sponsored placements.