Modern electric radiators must meet Lot 20 ecodesign rules in force since January 2018: accurate thermostats, timers and functions such as open window detection. At the electricity unit rate of 26.11p per kWh under the Ofgem price cap from 1 July 2026, each kilowatt of output costs about 26p per hour at full power, with thermostatic cycling reducing real costs once a room reaches temperature.
TL;DR · LAST REVIEWED 25 JULY 2026
- Lot 20 rules since January 2018 require thermostats, timers and efficiency functions on every electric heater sold
- Running cost at the July 2026 cap: about 26p per kWh, before thermostatic cycling reduces real world use
- Panel radiators suit standard tariffs and rooms used in bursts; oil filled retain heat; infrared heats people and surfaces directly
- Storage heaters on Economy 7 charge overnight at off peak rates: cheaper per unit when used well, weaker on control
- Electricity remains several times gas per unit of heat, so electric radiators win in homes without gas, flats and single rooms
| Type | Character | Best suited to |
| Dry thermal panel | Fast heat, none retained once off | Standard tariffs, rooms used in bursts |
| Oil filled | Slower to warm, retains heat after switch off | Living rooms and long evenings |
| Infrared panel | Heats people and surfaces, not air | Draughty or high ceilinged spaces |
| Smart WiFi | App scheduling, per room control | Cutting waste through precise schedules |
| Fan assisted | Instant warm air, some noise | Quick heat in small rooms and offices |
KEY FACTS
- Ofgem price cap electricity unit rate from 1 July 2026: 26.11p per kWh
- Lot 20 ecodesign rules in force since January 2018 for all electric heaters sold in the UK
- Prices run from around £62 for budget oil filled models to several hundred pounds for smart glass panels
- Rough sizing: 500W small bedrooms and offices, about 1,000W mid rooms, 1,500W to 2,500W large or poorly insulated rooms
- Replacing eight storage heaters with electric radiators costs roughly £600 to £1,000 in labour depending on wattage
- User reports on smart models commonly cite around 30p per hour at comfortable eco settings
Running costs, honestly
Electricity costs several times gas per unit of heat, so whole house electric heating in a gas connected home rarely wins on cost. Electric radiators earn their place in homes without gas, flats, extensions and single rooms, where precise control avoids heating unused space.
A thermostatic radiator cycling once the room is at temperature costs materially less than a basic heater running continuously at full power. Insulation cuts every number involved: loft and cavity wall insulation are both worth pricing for any home on electric heat.
Electric radiators versus storage heaters
Storage heaters charge overnight on Economy 7 off peak rates and release heat through the day, with running costs that can undercut daytime electric heating substantially when sized and used correctly. Their weakness is control.
Heat arrives on the charge schedule rather than on demand, and older models leak warmth into empty daytime rooms then run cold by evening. Modern high heat retention units with adaptive charging narrow the gap; panel radiators on a standard 24 hour tariff win on controllability. The tariff decides: panel radiators make little sense as primary heating on Economy 7, and storage heaters make little sense without it.
Sizing and installation
Wattage sizing matters more than brand: an undersized radiator runs constantly and costs more than a correctly sized unit cycling on and off. Rough markers run 500W for small bedrooms, around 1,000W for mid rooms, and 1,500W to 2,500W for large or poorly insulated spaces.
Most units plug in or wall mount as DIY jobs. Replacing a house of storage heaters involves removal and electrical work: around £600 to £1,000 in labour for an eight heater home depending on replacement wattage, before hardware.
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DISCLAIMER
This article is editorial information, not financial advice. Kael Tripton Ltd is not authorised or regulated by the Financial Conduct Authority. Figures were correct at the last review date shown above; verify current rates and rules with the primary sources listed below before acting.
Frequently asked questions
How much does an electric radiator cost to run?
At the July 2026 capped unit rate of 26.11p per kWh, each kilowatt of output costs about 26p per hour at full power. Thermostatic cycling reduces the real cost once the room reaches temperature.
Are electric radiators cheaper than storage heaters?
On a standard tariff, controllable radiators usually waste less than old storage heaters. On Economy 7, a well used modern storage heater can cost less per unit of heat. The tariff and the heater's age decide it.
What is Lot 20?
Ecodesign regulations in force since January 2018 requiring all electric heaters sold in the UK to include efficiency features such as accurate thermostats, timers and open window detection.
Are electric radiators cheaper than gas central heating?
Per unit of heat, no. They win in homes without a gas supply, in single rooms, and where zoned control avoids heating empty space.
What size radiator does a room need?
Roughly 500W for small bedrooms and offices, 1,000W for mid rooms, 1,500W to 2,500W for large or poorly insulated rooms. Slight oversizing with thermostatic cycling beats undersizing.
Is installation expensive?
Most models are DIY plug in or wall mount jobs. Swapping out eight storage heaters runs roughly £600 to £1,000 in labour depending on wattage, before the radiators themselves.
SOURCES
- Ofgem: Energy price cap – accessed 25 July 2026
- GOV.UK: Energy related products regulation – accessed 25 July 2026
