A plug-in heater costs roughly three times more per hour than a gas central-heating system for the same heat output.
If you are wondering whether plugging in a portable electric heater is cheaper than turning on your gas central heating, the short answer is no. Based on October 2026 energy price cap rates from Ofgem, a 2 kW fan heater running for one hour costs about 71p, while a gas boiler delivering the same 2 kW of heat costs about 23p. The gap widens if you use an oil-filled radiator on a high setting (around 2.5 kW) or a halogen heater.
This comparison uses the standard variable tariff rates effective October–December 2026: 28.5p/kWh for electricity and 6.5p/kWh for gas (Ofgem, 2026). The calculation assumes 100% efficiency for electric heaters and 90% efficiency for a modern gas boiler (DESNZ, 2026). A plug-in heater is roughly three times more expensive per hour of use than gas central heating for the same heat output.
How the running cost per hour compares for each heater type
Different plug-in heaters draw different amounts of power, which directly affects your running cost. A 2 kW fan heater costs 57p/hour on a low setting (2 kW x 28.5p) and 71p/hour on high (2.5 kW). A 1.5 kW oil-filled radiator costs 43p/hour on medium and 57p/hour on high. A 2 kW halogen heater costs 57p/hour. By comparison, a gas central-heating boiler delivering the same 2 kW of heat costs about 14p/hour (2 kW ÷ 0.9 efficiency x 6.5p).
These figures are based on the October 2026 Ofgem standard variable tariff rates and assume a modern condensing boiler operating at 90% efficiency (Ofgem, 2026; DESNZ, 2026). The electricity cost per unit is 4.4 times higher than gas, so even a low-power 1.5 kW heater costs more per hour than gas central heating.
The three scenarios where a plug-in heater makes financial sense
Despite the higher per-hour running cost, there are three situations where a plug-in heater can save you money overall. First, heating a single room for one to two hours when the central heating is off, such as a home office used for a short video call. Second, supplementing a poorly insulated room where turning up the whole-house thermostat would waste heat in other rooms. Third, renting a property where you cannot install or control the central heating, and you only heat one room.
In each case, the plug-in heater saves the cost of heating the entire house, which can offset the higher per-kWh electricity price. The Energy Saving Trust notes that zone heating, heating only the room you are in, can reduce overall energy use if done selectively (Energy Saving Trust, 2026). However, for whole-house heating, gas central heating remains significantly cheaper.
Quick numbers plug-in heater vs central heating cost comparison
| Heater type | Power (kW) | Running cost per hour (p) | Running cost per 3-hour session (£) | Annual cost if used 2 hours/day for 90 days (£) |
|---|---|---|---|---|
| 2 kW fan heater | 2.0 | 57 | 1.71 | 102.60 |
| 2.5 kW fan heater | 2.5 | 71 | 2.13 | 127.80 |
| 1.5 kW oil-filled radiator | 1.5 | 43 | 1.29 | 77.40 |
| 2 kW halogen heater | 2.0 | 57 | 1.71 | 102.60 |
| Gas central heating (per 2 kW output) | 2.2* | 14 | 0.42 | 25.20 |
*Gas boiler input power required to deliver 2 kW output at 90% efficiency. All figures based on October 2026 Ofgem price cap rates (28.5p/kWh electricity, 6.5p/kWh gas) and 90% boiler efficiency (Ofgem, 2026; DESNZ, 2026).
The direct answer yes, plug-in heaters cost more per kWh of heat than central heating
Electricity costs 28.5p/kWh, gas costs 6.5p/kWh, making electricity 4.4 times more expensive per unit of energy. Even accounting for boiler efficiency (90%), gas still delivers heat at about 7.2p per kWh of useful heat, compared to 28.5p for electric. This means a plug-in heater costs roughly four times more for the same amount of heat.
The only exception is if you use a heat pump, but that is a separate central-heating system, not a plug-in heater. For standard electric resistance heaters, fan heaters, oil-filled radiators, halogen heaters, the unit cost of electricity is the decisive factor (Ofgem, 2026; DESNZ, 2026).
How to verify an electrician or installer for a fixed electric heater
For a plug-in heater, no certification is required, you simply plug it into a standard 13A socket. If you plan to install a hardwired electric heater (e.g., a fixed panel heater or storage heater), the installer must be registered with NICEIC or NAPIT for Part P compliance. For a gas central-heating system, the installer must be Gas Safe registered (Gas Safe Register, 2026).
For a heat pump or biomass boiler, the installer must be MCS certified to qualify for the Boiler Upgrade Scheme grant (MCS, 2026). Always check the register online before hiring: Gas Safe Register for gas, MCS website for renewables.
What the Boiler Upgrade Scheme means for your heating cost decision
The Boiler Upgrade Scheme (BUS) offers a £7,500 grant for an air-source heat pump and £7,500 for a ground-source heat pump (GOV.UK, 2026). A heat pump running costs roughly 10–12p/kWh of heat, which is lower than a plug-in heater but still higher than gas central heating at current rates. The grant makes a heat pump a viable alternative to gas, but it does not apply to plug-in heaters.
If you are considering a plug-in heater as a temporary fix, the BUS grant may make a full heat-pump installation more affordable long-term. The grant significantly reduces the upfront cost, and the running cost per kWh of heat is roughly half that of a plug-in heater (Energy Saving Trust, 2026).
