Independent comparisons. We may earn from shop links. More info

Oil filled radiator running cost

Updated: October 2026

A listing calls the heater cheap to run, and you want the effect on the bill before you leave it on all evening. Oil filled radiator running cost, at full power, is the watts turned into kWh. A thermostat can shorten that time. It cannot give the oil a cheaper unit than a fan heater at the same watts. The [oil-filled radiator comparison](/hub/portable-heaters/oil-heater-fan) holds the nine models. Shelf prices there, from £34.99 to £171, are what the heater costs to buy. We did not meter these nine heaters. Figures are not a live tariff on 16 October 2026.

A listing calls the heater cheap to run, and you want the effect on the bill before you leave it on all evening. Oil filled radiator running cost, at full power, is the watts turned into kWh.

Our top picks

NETTA NETTA 11-fin 2500 W

Best overall

NETTA NETTA 11-fin 2500 W
7.7/10about £69.99
View offer
Dreo Dreo 9-fin smart 2000 W

Rank 2

Dreo Dreo 9-fin smart 2000 W
7.8/10about £118.99
View offer
Russell Hobbs Russell Hobbs 13-fin 2500 W with fan

Alternative

Russell Hobbs Russell Hobbs 13-fin 2500 W with fan
6.4/10about £82.99
View offer
On this page
  1. 1.Watts in, kWh on the meter
  2. 2.What a thermostat can shorten
  3. 3.One room or the whole house
  4. 4.What this set cannot tell you

Watts in, kWh on the meter

Energy Saving Trust states that a 2 kW heater at full power uses 2 kWh in an hour, whatever the type. A 2,500 W element uses 2.5 kWh in that hour. The Dreo's top step is 2,000 W. The NETTA, the Pro Breeze models and the Russell Hobbs state 2,500 W. The Status tops out at 2,000 W. The Russell Hobbs adds a stated 400 W turbo fan, an extra load only while that fan is on. The current field is 10.87 A, which matches about 2,500 W, so this page leaves a combined 2,900 W out. Your bill is those kWh times your unit rate. Compare 2.0 kWh or 2.5 kWh, then apply your rate.

What a thermostat can shorten

A thermostat saves money by switching the element off once the room is warm. A 2,500 W radiator flat out for four hours uses 10 kWh. The same radiator at full power for half that time uses 5 kWh. NETTA and Pro Breeze reviews call the heater expensive if it is left on high, which is that 2.5 kWh hour repeating. On the Dreo, several of the first 50 UK reviews say eco reads high or low, or cuts out early. That label is not a measured cut in kWh. A timer on the NETTA, the white Pro Breeze or the Dreo cuts hours only when it matches the time you are in the room. The versus fan heater page makes the same point for a blower.
NETTA NETTA 11-fin 2500 W

Testsieger

NETTA NETTA 11-fin 2500 W
7.7/10about £69.99
View offer

One room or the whole house

The Centre for Sustainable Energy's split is the useful one. Electric room heaters are usually a dear way to heat a whole home. Heating the one room you occupy can cost less than running the whole system for an empty house. A spare room for the evening can win: 12 to 20 m², a cycling thermostat, and the rest of the house left alone. A draughty lounge on 2,500 W from afternoon until midnight loses. The buying guide has the 100 W per square metre rule of thumb. For Great Britain, assimilated Commission Regulation (EU) 2015/1188 sets a 36 percent seasonal score and an occasional-use line. Northern Ireland's marking path differs from 1 July 2025.

What this set cannot tell you

No listing here publishes a measured pence-per-hour on a named UK tariff. A note of about £3 for four hours on one Russell Hobbs review is a single meter. The Dreo at 2,000 W has a lower full-power hour than a 2,500 W NETTA, and a thermostat that fails to cycle can wipe that gap out. This folder cannot crown a cheapest-to-run model. The best oil-filled radiator page names the Dreo and the NETTA for controls and price. Check your unit rate, multiply by 2.0 or 2.5 for a full-power hour, then shorten the hours with the dial.

Common questions

How many kWh does a 2,500 W oil radiator use in an hour?
At full power, 2,500 W is 2.5 kWh in one hour. A 2,000 W step is 2.0 kWh in one hour. Energy Saving Trust states the same identity for a 2 kW heater: 2 kWh in an hour at full power, any heater type. If a thermostat cycles, the hour contains less than that peak.
Is oil cheaper per hour than a fan heater at the same watts?
A 2 kW oil-filled radiator and a 2 kW fan heater each use 2 kWh in a full-power hour. Energy Saving Trust makes that comparison directly. Oil can stay warm after you switch off, so you may run fewer hours. The price of each full-power hour stays the watts times your unit rate.
Does eco mode cut the bill?
It cuts the bill only when it shortens the time the element draws power. On the Dreo, UK reviews dispute the eco sensor, with readings that run high or low or cut out early. Check a room thermometer before you bank a saving. A thermostat that cycles on a 1,000 W or 1,500 W step can cut kWh more reliably than a label you override.
What does 36 percent efficiency mean?
Under the Great Britain rules in assimilated Commission Regulation (EU) 2015/1188, a portable electric local space heater must reach at least 36 percent seasonal space heating energy efficiency. The figure is a seasonal control score, and the packaging must say the product suits well insulated spaces or occasional use. Electricity that reaches the element still becomes heat in the room while that element is on.
Is it cheaper than gas central heating?
It can be, when you heat one occupied room and you would otherwise run the whole system for an empty house. The Centre for Sustainable Energy makes that one-room point, and also says electric room heaters are usually a dear way to heat an entire home. Your gas tariff, your boiler and the number of rooms decide the sum.
Why did the bill jump when I left it on low all day?
A low step still draws power for every hour it is on. A 1,000 W setting for ten hours is 10 kWh, the same energy as 2,500 W for four hours. A timer that matches the hours you are there cuts that total. All-day background heat on electricity is the whole-home case the Centre for Sustainable Energy warns against.

Related pages

How to use an oil heater fan

Oil heater fan

Best oil filled radiator: Dreo pick or NETTA value

Oil filled radiator buying guide: watts, then timer

Oil filled radiator vs fan heater: which one to buy

Sources

Public UK sources from the research digest. Listing prices, stars and review counts are the amazon.co.uk lines used for this comparison, not a live check on 16 October 2026.

  1. Energy Saving Trust — Electric heaters compared (retrieved 16 October 2026)
  2. Centre for Sustainable Energy — Room heaters (retrieved 16 October 2026)
  3. Electrical Safety First — Portable heaters (retrieved 16 October 2026)
  4. GOV.UK — Fire safety in the winter (retrieved 16 October 2026)
  5. legislation.gov.uk — Regulation (EU) 2015/1188, Annex II (retrieved 16 October 2026)
  6. GOV.UK — Placing energy-related products on the UK market (retrieved 16 October 2026)
  7. Homebuilding & Renovating — Oil-filled radiator size (retrieved 16 October 2026)
  8. De'Longhi — TRD manual (first-use smell and upright use) (retrieved 16 October 2026)