The £25 fan heater from Argos is a famous trap. You buy it because it's cheaper than running the central heating for one room. You run it three hours a night for a winter. You spend £180 on electricity in pursuit of saving on gas. The £25 you saved on the heater costs £150 on the bill.
Portable heater economics in the UK are inverted from intuition: the cheapest to buy is the most expensive to run, and the slightly more expensive ones save genuine money across a winter. Pick by running cost, not purchase price.
The four types and what they actually do
There are essentially four categories of plug-in heater sold in the UK, and each has a specific use case where it earns its place.
Oil-filled radiators heat slowly, retain heat efficiently, and cycle their element on and off. A 1500W oil-filled radiator typically averages 600-900W of actual draw across an hour because it spends a lot of that hour at temperature, not actively heating. Best for sustained warmth in one room you'll actually occupy for hours. £60-£120 buys a competent one (Dimplex, Pro Breeze, De'Longhi).
Ceramic heaters warm up almost instantly using a ceramic plate. They draw their full rated wattage continuously when on, which makes them expensive for sustained use, but their fast response time makes them right for short bursts of heat. £30-£70.
Infrared and radiant heaters heat objects and people directly rather than warming the air. They're efficient for outdoor or semi-outdoor use (patios, garden offices, conservatories) where heating the air is futile because it just blows away. £50-£200 indoor, £100-£400 for outdoor patio versions.
Fan heaters are cheap, loud, and inefficient. They draw full wattage continuously, dry the air, and produce drafts that carry heat away from where you actually want it. The right answer is rarely a fan heater for sustained use; the right answer is sometimes a fan heater for a 5-minute pre-shower bathroom warm-up.
The running cost maths, properly
Running a heater four hours a day for ninety cold-weather days, at the standard 28p/kWh electricity rate that most UK homes pay in early 2026:
| Type | Average draw | Hours/winter | Cost/winter |
|---|---|---|---|
| Oil-filled radiator | ~750W | 360 | ~£75 |
| Infrared (1000W) | ~1000W | 360 | ~£100 |
| Ceramic (1500W) | ~1500W | 360 | ~£150 |
| Fan heater (2000W) | ~2000W | 360 | ~£200 |
The £40 difference in purchase price between a fan heater and an oil-filled radiator pays itself back in about three weeks of winter use. After that, the oil-filled keeps saving money.
The further variable: if you're on Octopus Cosy or a similar Economy 7 / time-of-use tariff, the cost during cheap hours can be 12-15p/kWh instead of 28p, which roughly halves the cost of running anything. For households on time-of-use tariffs, running the heater hard during the cheap window and letting the room coast warm through the expensive hours is the right pattern.
When portable heaters make sense at all
Portable heaters are right for a specific UK use case: heating one room you actively use, for a few hours, while keeping the rest of the house cooler. The classic setup is the home worker who heats a single home office during the day, while the rest of the house stays at 14-16°C, instead of running central heating throughout an empty four-bedroom semi.
For this use case, an oil-filled radiator costs roughly £60-£100 across a winter, versus running gas central heating throughout the house for the same period at typically £400-£700. The saving is real and meaningful.
The cases where portable heaters are wrong:
If you're heating multiple rooms simultaneously, the central heating is cheaper per room than running multiple electric heaters. Gas at roughly 6-7p/kWh in early 2026 beats electricity at 28p/kWh by a wide margin, even before accounting for boiler efficiency.
If you're using portable heaters because the central heating doesn't reach a particular room well, the right fix is the heating system, not a permanent electric supplement. The portable heater is a sticking plaster on a £200-£500/year wound.
If you're using a portable heater because the house is uninsulated and bleeds heat, the underlying fix is insulation. Loft insulation at £400-£700 pays back in 2-4 years and changes the maths on every other heating decision.
The use cases each type genuinely owns
Home office, kitchen extension, conservatory in spring/autumn. Oil-filled radiator. Slow start, long sustained warmth, cheap-ish to run. Set it on the medium setting, leave it for the morning, accept that it takes 20 minutes to feel warm.
Bathroom, brief pre-shower warm-up. Ceramic or fan heater. The room is small, you only need 5-10 minutes, and the fast response time matters more than the running cost. A £40 ceramic heater used for 10 minutes a day is fine.
Garage workshop, garden office, anywhere semi-outdoor. Infrared heater. The space leaks heat too quickly for warming the air to be useful; heating the person directly works better.
Patio in winter (the post-Christmas socialising scenario). Outdoor patio heater, infrared or radiant. Calor gas patio heaters work better outdoors than electric in many cases, but require gas bottle handling. Electric infrared is convenient if there's an outdoor socket.
Emergency / boiler-failure heating for a few days. Whatever you've got. The fan heater you mentally ruled out earlier is fine for three days while you wait for the engineer. It's only the wrong choice for sustained winter-long use.
What works in combination
The cheapest way to be warm in one room in winter, in 2026, is layered: a base layer of clothing, decent slippers, an oil-filled radiator on a lower setting than you think you need, and an electric blanket for the seating area. The combination produces sustained warmth at running cost roughly half of "crank the radiator on full and wear normal clothing".
Heated throws (£20-£50) are a slightly different category, working on the same heat-the-person principle as electric blankets. For sofa use during evening TV, a heated throw uses roughly 100W versus 1500W for a portable heater pointed at the sofa.
Hot water bottles (£8-£20) are still the cheapest personal warmth in existence. Dismissed by adults more often than they should be.
Layered indoor clothing — proper wool jumpers, slipper socks, a wool throw on the sofa — costs roughly £100 once and lasts a decade, and changes the temperature you can comfortably keep the house at by 2-3°C. Across a winter, that's £150-£300 of heating cost avoided.
What I'd actually do
For a UK home worker heating one room, four to eight hours a day, through winter: oil-filled radiator at £80-£100 (Dimplex OFC2000 or Pro Breeze 2500W). Set it on medium. Don't leave it running when you leave the room. Octopus Cosy or similar time-of-use tariff if you can switch.
For occasional bathroom use or quick warm-ups: cheap ceramic heater at £30-£50. Don't overthink it.
For a poorly insulated room with central heating that doesn't reach: fix the insulation and the central heating zoning before adding a portable heater. The loft insulation and smart thermostat approach is more cost-effective than running an oil-filled radiator forever.
The general principle holds across the category: pick by running cost, not purchase price. The £25 fan heater is the most expensive heater in the catalogue across one winter of actual use.
Affiliate disclosure: Morningfold has affiliate partnerships with Dimplex, Pro Breeze, Russell Hobbs. See editorial standards.