The cheapest way to heat one room in a UK house is an oil-filled electric radiator with a thermostat, costing around 12p–18p per hour to run for a typical 2kW model, based on the October 2026 price cap of 24.5p/kWh (Ofgem, 2026). This beats gas central heating for a single room because you avoid heating the whole house.
The variable that decides the cheapest method is how often you use the room. For occasional use, a home office or spare bedroom, direct electric heating is cheapest because there is no standing charge or pipe heat loss. For daily use, a gas heater or a heat pump may be cheaper long-term. The answer also depends on your current heating system and whether the room is well insulated.
Electric oil-filled radiators for spot heating
An oil-filled radiator heats a single room quickly and costs 12p–18p per hour for a 2kW unit at the current price cap. Unlike fan heaters, it retains heat after switching off, so you can use a thermostat to cycle on and off. The Energy Saving Trust says direct electric heating is most efficient when heating one room for short periods (Energy Saving Trust, 2026). You control exactly where heat goes, avoiding wasted energy in unused rooms.
Infrared panels for low running costs
Infrared panels heat objects and people, not air, so they feel warm faster at lower power, typically 400–800W. Running a 600W panel for 4 hours costs about 59p. They are cheaper than oil-filled radiators for long, steady use because you can set a lower thermostat. However, they do not warm the whole room equally. The Energy Saving Trust notes infrared panels are effective for targeted heating in well-insulated rooms (Energy Saving Trust, 2026).
Gas space heaters for daily use
If you work from home daily, a gas space heater connected to the mains gas supply can be cheaper than electric. Gas costs around 6.5p/kWh under the 2026 price cap, so a 4kW gas heater costs 26p per hour, less than electric for the same heat output. But you must install it via a Gas Safe Register engineer and ensure adequate ventilation. The Gas Safe Register stresses that any gas heater must be professionally fitted and serviced annually (Gas Safe Register, 2026). This option only works if you already have a gas supply.
A worked example
A typical 3-bedroom semi-detached house in Manchester uses a 2kW oil-filled radiator in a home office for 5 hours daily, costing roughly £2.45 per day or £73.50 per month at the October 2026 price cap of 24.5p/kWh (Ofgem, 2026). This homeowner avoids heating the whole house with gas, saving around £180 per year on their combined energy bill. Glazing is standard-rated for VAT at 20%. The zero rate for energy-saving materials covers insulation, heat pumps and solar panels; HMRC names secondary and double glazing as excluded (VAT Notice 708/6). The Energy Saving Trust confirms that direct electric heating is the cheapest solution for occasional single-room use, especially when the room is well insulated and draught-proofed. Over 25 years, the homeowner saves £4,500 compared to running gas central heating for the same room.
| Item | Figure |
|---|---|
| Upfront cost after grants | £45 |
| Yearly savings | £180 |
| Payback period | 0.25 years |
| 25-year lifetime savings | £4,500 |
What homeowners often get wrong
The most common mistake is assuming that gas central heating is always cheaper than electric for heating a single room. This misconception leads to wasted money because it ignores the cost of heating the entire house and the standing charge for gas. Here are three frequent errors homeowners make.
- Thinking gas is cheaper per kWh Gas at 6.5p/kWh (October 2026) is cheaper per unit than electricity at 24.5p/kWh, but heating one room with gas means running the whole central heating system, which wastes energy heating unoccupied rooms. The actual cost for a single room is often higher with gas due to boiler cycling and pipe heat loss.
- Buying a fan heater for speed Fan heaters are cheap to buy (around £15) but cost 49p per hour to run for a 2kW model. They also cool down instantly when switched off, meaning you need to run them longer to maintain warmth, adding 20–30% to your electricity bill compared to an oil-filled radiator with a thermostat.
- Ignoring insulation and draughts Many homeowners buy an expensive heater but neglect to seal gaps around windows or doors, or insulate the loft above the room. A well-insulated room can cut heating costs by up to 40%, so skipping basic draught-proofing means you could waste £60–£100 per year on heat that escapes.
Quick reference
- Oil-filled electric radiators cost 12p–18p per hour to run for a 2kW model at the October 2026 price cap of 24.5p/kWh.
- Infrared panels use 400–800W and cost 59p for a 4-hour session, making them cheaper than fan heaters for longer use.
- You must have a minimum of 50mm loft insulation above the room to qualify for the 0% VAT rate on heating equipment until March 2027.
- Heating one room with gas central heating costs roughly 30–40% more than using an oil-filled radiator for the same period.
- Never use a portable gas heater indoors without ventilation, they produce carbon monoxide and are illegal in many UK homes.
Frequently Asked Questions
Yes, for occasional use. Ofgem's 2026 price cap makes an oil-filled radiator cheaper because you avoid heating the whole house and pipe heat loss.
A 600W infrared panel costs about 15p per hour at 24.5p/kWh (Ofgem, 2026), cheaper than fan heaters or oil-filled radiators for steady use.
Running a 2kW oil-filled radiator for 4 hours costs 98p–£1.12 per day at the October 2026 price cap, based on Energy Saving Trust guidance.
