Cheapest Way to Heat a Room
Gas, oil, a plug-in electric heater, storage heaters or an air-con heat pump: compare what it really costs to heat a room per hour, per month and per winter, with typical prices for the UK, Ireland and eight other European countries.
No sign-up required. Free to use, with every formula shown on this page. Prices checked October 2026.
Compare heating costs
Room Heating Cost Comparison
Every heater has to put the same heat into your room. See what that heat costs with gas, oil, a plug-in electric heater, storage heaters or an air-con heat pump, per hour, per month and per winter.
1 Your room
Fills in typical prices for step 2. You can change any of them.
About 1,2 kW of heat while the heating is on.
Filled in for where you live: roughly the length of the heating season. Mild coastal areas need fewer days; cold, high or exposed homes need more.
2 Your prices
Unit prices from your bill or your last delivery. Standing charges are left out: you pay them whichever heater you use.
3 Heaters to compare
Tick the ones you have or are thinking of buying. A price to buy is optional; add it to see how long a dearer heater takes to pay for itself.
Most boilers fitted since about 2005 are condensing.
Heat out for each unit of electricity. 3,5 is a cautious figure for cold days.
Cheapest to run
Air-con heat pump
0
a winter
Per hour
0
Per month
0
Heat used a winter
0 kWh
Cost per winter, same heat
Or heat yourself, not the room
It keeps one person warm, not the room, so it suits sitting still in a chilly room, not a family room or a damp one.
Butane heaters: burning 1 kg of gas puts about 1,6 litres of water into the room, so keep a window slightly open and watch for condensation (the Dehumidifier Selector can help). Never use one in a bedroom or bathroom, and fit a carbon monoxide alarm.
Cold rooms get damp: a poorly insulated room that's heated for only a few hours a day is more likely to get condensation and mould. Check it with the Damp & Mould Risk Checker.
How it's worked out: heat needed = room size × 40, 60 or 90 W per m² (by insulation) × hours a day. Cost of 1 kWh of heat = fuel price ÷ (energy in the fuel × efficiency): electric heaters and storage heaters 100%, heat pump = SCOP, condensing boilers 90% (older gas 75%, older oil 80%), heating oil 10,18 kWh a litre (kerosene) or 10,0 (gas oil), butane 12,7 kWh a kg, pellets 4,7 kWh a kg at 88%. A month is 30 days. Prices checked October 2026: UK from Ofgem's price cap (1 October to 31 December 2026); Ireland from SEAI (1 July 2026) and current supplier and oil prices; Spain from regulated prices; other countries from Eurostat (second half of 2025) and the EU Weekly Oil Bulletin (5 October 2026); pellets from national pellet associations.
Estimates only. Actual costs vary with the weather, your thermostat settings, how airtight the room is, and your tariff.
How it works
Same heat, different price
Every heater has to put the same amount of heat into your room. What changes is how much each unit of that heat costs you, and that depends on two things: the price of the fuel and how much of it ends up as heat. The sources and assumptions behind it are on our How we calculate page.
How much heat the room needs
The calculator works out the heat from the room size and how well it’s insulated: about 40, 60 or 90 watts per square metre while the heating is on. Multiply by the hours a day and the days in a winter, and you have the heat to buy.
How much of the fuel becomes heat
Plug-in heaters turn every kWh of electricity into a kWh of heat. Condensing boilers manage about 90%. An air-con heat pump moves heat in from outside, so it gives about 3 to 4 kWh of heat for each kWh of electricity.
What the fuel costs where you live
Pick your country and the calculator fills in typical prices for electricity, gas, heating oil and more. Change any of them to match your bill. Standing charges are left out, because you pay them whichever heater you use.
Examples
What one room costs to heat for a winter
The same room, the same heat, very different bills. These examples use the calculator’s own figures and typical prices for each country.
Illustrative only: a 20 m² room with average insulation (about 1.2 kW of heat), heated 5 hours a day for 180 days (UK and Ireland) or 200 days (Germany), with condensing boilers and a heat pump SCOP of 3.5. Prices checked October 2026: UK Ofgem price cap; Ireland SEAI and current oil prices; Germany Eurostat and the EU Weekly Oil Bulletin. Storage heaters in the UK depend on your Economy 7 night rate. Your own costs will differ.
Ways to save
How to heat a room for less
Once you know what each kWh of heat costs you, the cheapest wins come from using the right heater for the job and keeping the heat in.
Heat the room you’re in
Central heating warms every room with a radiator. If you only need one room for an evening, turn the other radiators down and compare: a plug-in heater costs more per kWh, but it may still cost less than heating the whole house.
Keep the heat in
Draught-proof doors and windows, close curtains at dusk and shut doors to unheated rooms. A room that loses less heat needs a smaller heater for fewer hours, whatever it runs on.
Heat yourself, not the room
If you’re sitting still on your own, a heated throw or electric blanket keeps you warm for a few pence an hour. Keep rooms from getting very cold, though: cold walls attract condensation and mould. Our Damp & Mould Check shows the risk.
Explore more tools
More practical tools, all in one place
Use simple checks, pickers and planners to make better decisions about your home, equipment and energy use.
Electricity Cost Calculator
Find out how much your appliances cost to run per day, month and year.
Replace or Keep
Compare the running cost of your current appliance with potential replacements.
Dehumidifier Picker
Find the right size and type of dehumidifier based on your room and usage.
Off-Grid Planner
Estimate your daily power needs and the battery, solar and inverter capacity to supply them.
Damp & Mould Check
Check whether a window or wall will get condensation or mould, and what humidity keeps it dry.
Plug-in Solar Payback
See what a plug-in (balcony) solar kit would save and how many years it takes to pay for itself.
Radiator & BTU Calculator
Work out what size radiator a room needs, in watts and BTU, for a boiler or a heat pump.
Paint Calculator
Work out how much paint a room or the outside of a house needs, and which tins to buy.
Concrete Calculator
Work out the concrete for a slab, footing, fence posts or steps, and the cement, ballast or bags to buy.
Tile Calculator
Work out how many tiles, boxes, adhesive and grout a floor or wall needs.
Wallpaper Calculator
Work out how many rolls of wallpaper a room or feature wall needs, allowing for the pattern repeat.
Square Metre Calculator
Work out the area of a room, floor or garden in m² and ft², including L-shapes and circles.
Gravel Calculator
Work out the tonnes and bags of gravel, chippings or sub-base for a path, border or driveway.
Decking Calculator
Work out the deck boards, joists and screws or clips for a timber or composite deck.
Flooring Calculator
Work out the packs of laminate, wood or click vinyl flooring a room needs, with underlay and beading.
Solar Panel Calculator
See what solar panels on your roof would make and save, and how many years they take to pay back.
Heat Loss Calculator
Estimate your whole home's heat loss, the heat pump size it needs and what heating costs a year.
Cable Size Calculator
Work out the cable size and fuse for a 12 V, 24 V or 48 V circuit in a van, boat or off-grid system.
EV Charging Cost
See what an electric car costs to charge per mile, per charge and per year, and the saving over petrol.
Laundry Symbols
Tap the symbols on a care label to see what they mean and the wash, dry and iron settings to use.
U-Value Calculator
Build up a wall, loft, roof or floor layer by layer to see its U-value and what its heat loss costs.
Curtain Size Calculator
Work out the pole length, curtain width and drop, the ready-made size to buy and the fabric to make them.
TV Size Calculator
Find the best TV size for where you sit, or the best seat for your TV, and how high to mount it.
Light Bulb Finder
Find the fitting, brightness and colour of the LED to replace any bulb, and keep a list of your bulbs.
Common questions
Frequently asked questions about heating costs
Common questions about heaters, heat pumps and what heating a room really costs.
Are oil-filled radiators cheaper to run?
No. Oil-filled radiators, convector heaters, fan heaters, ceramic heaters and infrared panels all turn 1 kWh of electricity into 1 kWh of heat, so they cost the same to run for the same heat. Oil-filled radiators just release their heat more slowly, and infrared panels warm you directly, so they can feel different.
Is it cheaper to use a plug-in heater or the central heating for one room?
Per kWh of heat, gas central heating is usually around three times cheaper than a plug-in electric heater. But central heating warms every room with a radiator, so for one small room for a short time a plug-in heater can cost less overall. Turning other radiators down narrows the gap.
Is it cheaper to leave the heating on low all day?
Usually not. A warm home loses heat faster than a cool one, so heating only when you need it normally uses less energy. Heat pumps are the exception: they work best running steadily at a lower temperature. Don’t let rooms get very cold for long, though, as cold walls attract condensation and mould.
How much does a heated throw cost to run?
A typical heated throw or electric blanket uses about 150 W on its highest setting. Five hours a day is 0.75 kWh, about 20p at the UK price cap from October 2026, or about 29 cents at Irish prices. Most run on a lower setting much of the time, so they often cost less.
Are storage heaters cheap to run?
They charge up overnight on a cheaper night rate, so each kWh costs less than daytime electricity. But some of the stored heat leaks out before the evening, and if the heat runs out you may top up at the full price. The calculator shows the best case; real costs are often higher.
How much does an air-con heat pump cost to run per hour?
For a typical 20 m² room needing about 1.2 kW of heat, a heat pump with a seasonal efficiency (SCOP) of 3.5 uses about 0.34 kWh of electricity an hour. That’s about 9p at the UK price cap or about 13 cents at Irish prices.
Are the results exact?
No. They are estimates based on average heat needs, typical efficiencies and average prices. Real costs depend on the weather, your thermostat settings, how airtight the room is and your tariff, so enter your own prices for the closest figures.