Immersion heaters are typically known for high electrical consumption, says Peter Clayton from Trade Plumbing. This is mainly down to the fact that they cannot be used to heat small amounts of water, but rather a full tank for each use.
On average an immersion heater uses 3kW per hour, with the current energy price cap of 27p/kWh that is roughly 81p per hour. Immersion heaters can take anywhere from one to two hours to heat up so they have the potential to cost £1.62 alone to heat up.
Immersion heaters can be very expensive for those who are looking for a constant supply of hot water. The installation of a thermostat allows homeowners to keep their immersion heater on constantly, but at a lower temperature so it uses less electricity throughout the day and is less time consuming when it comes to heating up.