Estimate daily, weekly and yearly electric heater cost using wattage, time used, heating pattern and your electricity rate.
Last reviewed: 16 April 2026 - UK-focused estimate, not a supplier quote
Electric heaters can look cheap for short bursts and expensive very quickly in regular use. The biggest drivers are heater size, how long it stays near full power, and whether the room is a poor fit for the heater in the first place.
This works best when you know the wattage and have a realistic sense of how hard the heater works once the room settles.
Most electric heaters do not stay at full power the whole time. A lower percentage is usually more realistic once the room has warmed up.
A 1,500W heater used for four hours a day, five days a week, does not need to run flat out to become a noticeable winter cost.
If a heater is too small for the room, the duty cycle can stay stubbornly high and the "cheap" option stops feeling cheap.
Room size, insulation, heater wattage and time in use usually matter far more than small differences between direct electric heater brands or marketing claims.