The cheaper option depends on whether you need one room warm for a short time or a whole home warm for longer.
A plug-in electric heater can make sense for short single-room use, but central heating often wins when several rooms need heat.
Use this as decision logic before modelling your exact heater or whole-home setup.
Current rate used: 24.67p/kWh electricity, 5.74p/kWh gas, based on Ofgem price cap, 1 April to 30 June 2026 for Direct Debit customers. Your actual tariff can differ by supplier, region, payment method and meter type.
The full-power column is the clean benchmark. The 65% column is a more realistic starting point for a thermostat-controlled heater in a warmed-up room.
| Heater size | Cost per hour | 4 hours | 7 days at 4h/day | 30 days at 4h/day | 30 days at 65% average output |
|---|---|---|---|---|---|
| 500W | £0.12 | £0.49 | £3.45 | £14.80 | £9.62 |
| 1kW | £0.25 | £0.99 | £6.91 | £29.60 | £19.24 |
| 1.5kW | £0.37 | £1.48 | £10.36 | £44.41 | £28.86 |
| 2kW | £0.49 | £1.97 | £13.82 | £59.21 | £38.49 |
| 2.5kW | £0.62 | £2.47 | £17.27 | £74.01 | £48.11 |
(watts / 1000) x hours x electricity price per kWh
For this page's 2kW example, 4 hours at full output costs £1.97. Used the same way for 30 days, it costs £59.21; at 65% average output it is closer to £38.49.
Short answers to the questions this page is built to solve.
Sometimes, especially for short use when you do not need the whole home warm. For longer sessions or multiple rooms, central heating may be cheaper overall.
Not as a blanket rule. Model the room, hours and comfort need first, because direct electric heat can become expensive quickly.