How Much Does It Cost to Run a Oil-Filled Radiator? (UK 2026)
Based on the active UK Ofgem price cap of 24.5p per kWh (1 January 2026 – 31 March 2026).
A typical 1500W oil-filled radiator costs £0.37 per hour of continuous use at current UK electricity rates (24.5p/kWh). For typical daily usage (4 hours daily during cold spells (cycling via thermostat)), it costs approximately £1.47 per day or £535.97 per year.
Manufacturer specs: Dimplex & De'Longhi Dragon4 electric oil radiator series (1.5 kW medium model)
* Includes 0.5W standby consumption outside active hours (£0.89/year).
How to Save Money Running a Oil-Filled Radiator
- Position the oil radiator centrally or beneath a window to generate natural thermal convection currents throughout the room.
- Use the medium power toggle (e.g. 1000W instead of 2000W) once the room is warm to maintain comfort without high peak demand.
- Take advantage of the thermal retention: oil remains hot and radiates heat for 30–45 minutes after switching the unit off.
- Fit a 24-hour plug-in mechanical timer so the radiator warms your bedroom 30 minutes before waking without running all night.
Alternative Appliances Compared
vs. Electric Fan Heater
View running cost →Fan heaters are noisier and blow dust, while oil radiators operate in total silence and maintain stable temperatures via oil thermal inertia.
vs. Electric Blanket
View running cost →For personal warmth while watching television or sleeping, an electric blanket draws 100W versus 1500W for an oil radiator.
Oil-Filled Radiator Technical Power Profile
Source data: Dimplex & De'Longhi Dragon4 electric oil radiator series (1.5 kW medium model)
Frequently Asked Questions: Oil-Filled Radiator Electricity Costs
How much does it cost to run an oil-filled radiator for 4 hours in the UK?â–¾
A 1500W radiator running at an average 60% thermostat duty cycle uses approx. 3.6 kWh over 4 hours. At 24.5p/kWh, that costs about 88p per session or £26.40 per month.
Does an oil-filled radiator use electricity continuously?â–¾
No. Once the thermal fluid reaches the set temperature, the thermostat clicks off and stops drawing power. In a sealed room, the heating element is typically active only 50% to 65% of the time.
Do you ever need to refill the oil in an oil-filled radiator?â–¾
No. The diathermic thermodynamic oil inside the radiator is permanently sealed at the factory and never degrades, evaporates, or needs replenishment.
Are oil-filled radiators cheaper to run than fan heaters?â–¾
Over extended multi-hour sessions, yes. Because oil stores thermal energy and releases it gradually, the thermostat cycles on and off less erratically than a fan heater, providing steadier comfort with lower cumulative consumption.
What size oil-filled radiator do I need for a 15 square metre room?â–¾
A standard rule of thumb for UK and European homes is approx. 80W to 100W per square metre. For a 15 m² room with normal ceiling height and insulation, a 1500W model is ideal.