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Understand what you use, what it costs, and what could change. Free calculators for electricity, solar, heat pumps and electric vehicles.
What does one hour of heating cost?
Suppose a 2,000 W electric heater draws its full power for one hour. At an assumed £0.25 per kWh, that hour costs £0.50. The price is a fictional example, not a current UK tariff.
Calculate with your own power and price ↗- Convert the power. 2,000 W ÷ 1,000 = 2 kW.
- Calculate the energy. 2 kW × 1 hour = 2 kWh.
- Apply the price. 2 kWh × £0.25/kWh = £0.50.
- Count actual use. One hour on 90 days uses 180 kWh and costs £45.
A 1,000 W heater running for two hours uses the same 2 kWh. A lower power rating alone does not mean a lower energy bill. Thermostats change actual operating time; use measured kWh when the appliance cycles. Fixed daily charges are separate.
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Your currency. Your context.A useful estimate starts
with clear assumptions.
Use the power on your appliance, the unit rate on your electricity bill, or your actual meter readings. See the formula and adjust every assumption.
Reference prices are dated benchmarks or clearly marked examples, not live tariffs. Solar and heating estimates help you explore a scenario; they are not installation quotes.
Check what your estimate includes.
EnergyCalc separates consumption, prices and assumptions so you can compare one change at a time. Each tool includes its formula, an example and the limits of the calculation.
Appliances that switch on and off
A fridge or washing machine does not draw its maximum power throughout the day. Use measured energy or the appropriate annual or per-cycle figure from its documentation.
Prices that depend on time or consumption
A single price cannot reproduce every bill. Calculate separate price periods or tariff bands, and keep fixed fees separate. Saving electricity and moving usage to a cheaper period have different effects.
Solar, heating and vehicle comparisons
Solar savings depend on when generation meets demand and how exports are valued. Heat pumps need a realistic seasonal performance assumption. EV comparisons must use a consistent boundary for charging losses. Simple payback excludes financing and other ownership costs described beside each tool.
Read the calculation methodology ↗