Electric heaters are a popular supplementary heating option in UK homes, especially in rooms without radiators or when you want to heat a single space without turning on the whole central heating system. However, because electricity costs approximately 4 times more per kWh than gas (24.5p vs 6.5p), electric heaters are one of the most expensive ways to heat a room. Understanding the costs helps you use them wisely.
Quick Answer: Electric Heater Running Costs
Based on the UK average electricity rate of approximately 24.5p per kWh:
| Heater Type | Typical Wattage | Cost Per Hour | Cost Per Evening (4 hrs) | Monthly (4 hrs/day, 30 days) |
|---|---|---|---|---|
| Fan heater | 2,000 – 3,000W | 49p – 74p | £1.96 – £2.94 | £58.80 – £88.20 |
| Oil-filled radiator | 1,500 – 2,500W | 37p – 61p | £1.47 – £2.45 | £44.10 – £73.50 |
| Convector heater | 1,000 – 3,000W | 25p – 74p | £0.98 – £2.94 | £29.40 – £88.20 |
| Halogen heater | 400 – 1,200W | 10p – 29p | £0.39 – £1.18 | £11.76 – £35.28 |
| Panel heater | 1,000 – 2,000W | 25p – 49p | £0.98 – £1.96 | £29.40 – £58.80 |
| Infrared heater | 300 – 1,800W | 7p – 44p | £0.29 – £1.76 | £8.82 – £52.92 |
Important: Running a 2kW electric heater for 4 hours every evening for a month costs approximately £58.80. Over a 5-month winter season (November–March), that's nearly £295 on a single heater in one room. This is often more expensive than running gas central heating for the whole house.
Electric Heater Types Explained
Fan Heaters
Fan heaters blow air over a heated element, providing almost instant warmth. They're cheap to buy (£15–£40) but expensive to run at full power (2–3kW). They heat a room quickly but the warmth dissipates almost immediately when switched off. Best for: brief bursts of heat in small spaces (bathrooms, under desks).
Oil-Filled Radiators
These heat oil sealed inside metal fins, which then radiates warmth into the room. They take longer to warm up (15–30 minutes) but retain heat after switching off — the oil stays warm for 30–60 minutes. Many have thermostats that cycle the element on/off, meaning actual energy use is often 60–80% of rated wattage. Best for: sustained heating over several hours.
Convector Heaters
Convector heaters warm air that passes over an internal element, creating a natural convection current. They're quiet, relatively quick to warm a room, and available in a wide range of wattages. Best for: general room heating in medium-sized spaces.
Halogen/Radiant Heaters
These emit infrared radiation that heats objects and people directly rather than the air. They provide instant warmth in a focused direction but don't heat the whole room. At 400–1,200W, they're cheaper to run than convection heaters. Best for: personal warmth when you're stationary (desk work, watching TV).
Infrared Panel Heaters
Modern infrared panels mount on walls or ceilings and radiate gentle heat to objects in the room. They're very efficient for maintaining warmth in well-insulated spaces and can run at lower wattages (300–800W for a room panel). Best for: well-insulated rooms where you want consistent background warmth.
The Real Cost: Thermostat vs Constant Running
A critical factor many people miss: heaters with thermostats don't run at full power continuously. Once the room reaches the target temperature, the heater cycles off and only turns on again when the temperature drops:
With thermostat: A 2kW oil-filled radiator with a thermostat set to 20°C in a well-insulated room typically cycles at about 40–60% duty — meaning it actually uses 0.8–1.2 kWh per hour on average, not the full 2 kWh. This can halve your running costs compared to the "worst case" figures above.
Heaters without thermostats (basic fan heaters, halogen heaters) run at full power constantly until you manually switch them off — making them significantly more expensive if left unattended.
Electric Heater vs Gas Central Heating
Many people use electric heaters thinking "I'll just heat one room instead of the whole house" — but is this actually cheaper?
| Heating Method | Cost Per Hour (typical room) | Best For |
|---|---|---|
| Gas central heating (1 room via TRV) | 10p – 20p | Homes with gas boilers |
| Gas central heating (whole house) | £1.00 – £2.00 | When multiple rooms need heating |
| Electric heater (2kW) | 49p | No gas supply, temporary/supplementary |
| Electric heater (1kW with thermostat) | 15p – 25p (with cycling) | Small, well-insulated rooms |
The rule of thumb: if you have gas central heating, it's almost always cheaper to run your boiler than an electric heater — even for a single room. Electric heaters only make economic sense when:
- You don't have gas central heating
- You need heat for less than 1–2 hours (quicker than waiting for radiators to warm up)
- You want to heat a very small, enclosed space (bathroom, study)
- The room is far from your boiler and radiators are inadequate
Tips to Reduce Electric Heater Costs
- Use a heater with a thermostat — this prevents over-heating and cycling saves 30–50% of energy vs running constantly.
- Use a timer — don't leave heaters running when you're out or asleep. A £5 plug-in timer can save significant amounts.
- Match heater size to room — a 1kW heater is sufficient for a small bedroom. Using a 3kW heater in a small space wastes energy.
- Close doors and windows — heating escaping through gaps makes the heater work harder. Draught-proof the room first.
- Use radiant/infrared for personal warmth — if only you need warming (not the whole room), a 400W halogen heater directed at you is far cheaper than a 2kW convector heating the entire space.
- Insulate first — improving insulation (even simple measures like thick curtains, draught excluders, and rugs on bare floors) reduces the energy needed to maintain temperature.
- Layer up before reaching for the heater — wearing a jumper is equivalent to raising room temperature by 2–3°C.
- Consider an electric blanket — at 50–100W, an electric blanket costs just 1–2p per hour and keeps you warm in bed without heating the room.
Calculate Your Exact Heater Costs
Use our free energy cost calculator to work out exactly what your electric heater costs per day, month, and year. Enter the wattage (shown on the heater's label) and your typical daily usage hours.