Answer first
Running cost is broadly useful heat required ÷ seasonal system efficiency × electricity price. Each part can vary substantially between properties and households.
Compare measured room temperatures, weather and hot-water use before comparing bills. A larger home kept warmer should not be expected to match a smaller home that heats fewer rooms.
Interquartile SPFH4 range in the monitored demonstration sample
View sourceHeat loss should be calculated for each heated space
View sourceTariff comparisons must include all electricity use, not heating alone
View sourceUnderstand the likely running cost for your home
Share the property, current heating and the question holding up your decision. FLO will explain what to check next without pushing you into a survey.
The building sets the heat demand
Floor area, exposed walls, glazing, air leakage and target temperatures affect how much heat leaves the home. Weather and wind then change that demand day by day.
Insulation can reduce demand, but the calculation should reflect the actual fabric rather than a generic house type.
Water temperature changes efficiency
A heat pump generally works harder when asked to produce hotter water. Radiators, underfloor loops and pipework therefore influence electricity use through the flow temperature they require.
Weather compensation should lower the target water temperature in milder conditions instead of running one unnecessarily hot setting all season.
Controls and hot water matter
Deep setbacks, frequent boosts and permanent immersion use can add consumption. A sensible schedule usually maintains steady comfort and heats water in planned periods.
Occupancy changes matter too. More showers, an extension or newly heated rooms add useful heat demand even if the system settings are correct.
Compare evidence in context
Record outdoor temperature, room comfort and total electricity over representative periods. A raw monthly figure without those conditions can mislead.
If use looks abnormal, check the commissioned design, controller history and backup-heater operation before assuming the heat pump itself is defective.
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Questions people also ask
Does brand determine the bill?+
Brand matters, but heat demand, system temperatures, emitters, controls and tariff usually explain more.
Why did my bill rise in a cold week?+
The building needed more heat and heat-pump efficiency can fall as outdoor temperature drops.
Can I compare my bill with a neighbour?+
Only cautiously. Compare size, fabric, temperature, hot water, tariff and weather first.
Evidence used for this answer
Figures are explained in context and links go to the independent source. Prices, tariffs, scheme rules and standards can change, so check the source again before making a financial or technical decision.
- Energy Systems Catapult: heat-pump performance analysisMeasured seasonal performance and cold-weather operation from the Electrification of Heat demonstration project.
- MCS heat-pump design standardTechnical requirements for heat loss, equipment selection, domestic hot water and system design.
- Energy Saving Trust: the most efficient way to run a heat pumpGuidance on weather compensation, longer run periods, setbacks, radiators, hot water and smart energy use.
- Energy Saving Trust: time-of-use tariffsHow half-hourly smart tariffs work, when flexibility helps and what to compare before switching.