What does it cost to run? A better way to compare heating and cooling
Use electrical input, hours and your own tariff. Do not mistake cooling output for electricity consumption.
A headline equipment price answers one question: what does the item cost to buy? Running cost is a different calculation. Start with the electricity used, the time period and the unit rate on your own bill.
The basic calculation
Electricity cost = electrical input in kW × hours of operation × electricity price per kWh. If you already have measured energy use in kWh, multiply that by the unit rate instead. Standing charges are separate from this appliance-use calculation.
A deliberately simple example
Suppose an appliance draws a constant 1 kW for four hours, and the example tariff is £0.25 per kWh. It uses 4 kWh and costs £1 for that period. These are invented round numbers to demonstrate the calculation, not a current tariff quote or a performance claim for a product.
At the same example rate, 0.5 kW for four hours would cost £0.50. The comparison only means something if both options deliver the comfort or service you actually need.
Input is not output
A heating or cooling capacity figure is not automatically the electrical input to put into that calculation. Ask for the relevant input or consumption data for the operating conditions. A system that changes its output will not necessarily draw its rated maximum continuously.
Compare the same job
Write down the room, target conditions and hours you need it. Then check whether the figures you are comparing are measured, seasonal ratings, laboratory specifications or estimates. Keep those categories separate. A fan and an air conditioner do not deliver the same result, even if one uses less electricity.
Energy labels can help with comparisons, but consider the appliance's size and consumption figures as well as the letter rating. Energy Saving Trust explains appliance efficiency labels.
Turn the numbers into a buying question
Ask for the assumptions behind any running-cost illustration and what is included in the installed price. Use our finder to establish the product route, then discuss suitability and operating information before ordering.
Explainer. Prepared 7 October 2026. Examples illustrate arithmetic only; actual consumption and tariffs vary.
ClimateCart is a retailer. Alpha is our preferred manufacturer. Editorial policy & commercial disclosure.
