Energy Saving Trust says an air-source installation typically costs around £12,000 and can deliver more than three units of heat for each unit of electricity. Running expenditure cannot be inferred from that headline efficiency. The seasonal result depends on the dwelling’s heat demand, water temperatures, emitter capacity, controls and backup use, all of which must appear in the designer’s forecast.
For 1 October–31 December 2026, Ofgem’s Direct Debit averages put electricity at 26.32p/kWh; the corresponding gas figure is 7.97p/kWh. Use them only as dated context. The operating estimate must apply the household’s own tariff to calculated electricity demand and compare it with the actual gas terms, including any standing charge that disappears or remains.
Use seasonal coefficient of performance, often described as SCOP, rather than a laboratory COP at one outdoor temperature. The installer’s room-by-room heat-loss calculation, design flow temperature and emitter schedule should support the forecast.
Compare delivered heat on both sides. A gas boiler consumes more fuel than heat delivered because efficiency is below 100%; a heat pump consumes less electricity because it moves heat. Standing charges should be shown separately and removed only if the gas connection will actually be closed.
What changes the answer
Heat demand
Insulation, airtightness, floor area, weather and thermostat settings determine the heat the building needs.
Seasonal efficiency
Lower flow temperatures and correctly sized emitters generally support better performance. Require a design forecast.
Electricity tariff
A time-of-use heat-pump tariff can reduce cost, but model when the system will run and any peak restrictions.
Hot water
Cylinder temperature, sterilisation cycles and household draw affect electricity consumption.
Controls
Weather compensation and steady operation can outperform aggressive on-off schedules.
Gas standing charge
Count removal only when every gas appliance is replaced and the supply is formally disconnected.
Illustrative worked example
Illustrative example — a Newcastle semi needs 12,000 kWh of delivered space and water heat. At a seasonal efficiency of 3.2, electricity use is 12,000 ÷ 3.2 = 3,750 kWh. At Ofgem’s October–December 2026 average 26.32p rate, annual variable cost is 3,750 × £0.2632 = £987. By comparison, an 85%-efficient gas system needs 12,000 ÷ 0.85 = 14,118 kWh of gas; at 7.97p that is £1,125.20. Standing charges and tariff differences must be added separately.
Rules and responsibilities for this topic
Design standard
An MCS installation should be based on a room-by-room heat-loss calculation and documented emitter and control design.
Planning and noise
Permitted-development conditions and MCS 020 noise assessment may apply; protected properties can need additional consent.
Metering evidence
Keep commissioning settings and monitor electricity use and delivered comfort through a full heating season.
Build the running-cost estimate from heat demand
Request a room-by-room heat-loss calculation and the resulting annual space-heating and hot-water demand. Divide useful heat by the proposed seasonal performance factor to estimate electricity consumption; do not apply a peak COP from a brochure across the year. Add pumps, immersion use and controls where the designer expects them. Compare the result with the household’s present fuel use after allowing for boiler efficiency.
Flow temperature is central to the forecast. Check that radiators or underfloor heating can deliver each room’s design heat loss at the stated temperature, including cold-weather conditions. Oversized emitters and steady controls can improve efficiency, while frequent electric backup can undermine it. Ask the installer to show weather compensation settings, hot-water temperature and any assumed heating schedule. A promised annual figure without those design inputs cannot be audited.
Apply the actual electricity tariff and test a higher unit rate or lower seasonal efficiency. Separate standing charges, because removing gas may save its standing charge while a retained gas appliance will not. Compare comfort and operating pattern as well as cost; a continuously maintained temperature is different from short boiler bursts. Use the quote checker to flag missing calculations. Keep the design heat loss, emitter schedule and commissioning settings so later performance can be compared with what was sold.
Monitoring should be planned before installation. Agree which meters or controller readings will show electricity consumed and heat delivered, whether hot water can be separated, and how the household can export data. Compare performance over a heating season rather than reacting to one cold day. If consumption is higher than forecast, check settings, flow temperatures, schedules and backup-heater operation before assuming the equipment is faulty. A documented baseline also helps distinguish a change in weather or comfort from a genuine commissioning problem.
Check the forecast against a cold-weather case
Ask the designer for electricity consumption at the design outdoor temperature as well as the annual total. The cold-day result should identify heat-pump input, delivered heat and any supplementary heater. Compare it with the property’s electrical capacity and tariff period. This does not predict a whole winter, but it exposes a design that depends heavily on resistance heating when demand peaks. Once installed, note outdoor temperature and daily consumption during a representative cold spell, while keeping comfort settings steady, so commissioning can be reviewed with evidence rather than impressions.
Questions to ask the installer
- What annual heat demand does the survey calculate?
- What SCOP is forecast at the designed flow temperature?
- Which radiators or pipework must change?
- How is hot-water electricity included?
- Which tariff periods are assumed?
- What monitoring will reveal poor performance?
Frequently asked questions
Are heat pumps cheaper to run than gas boilers?
They can be, but the result depends on seasonal efficiency and the electricity-to-gas price ratio. Energy Saving Trust notes standard electricity can be nearly four times the gas price. Use the home’s heat demand and tariff instead of a generic promise.
What SCOP should I expect?
The appropriate figure is property- and system-specific. Energy Saving Trust says a well-designed unit can supply over three units of heat per unit of electricity as boilers, but actual seasonal performance depends on flow temperature, emitters, controls and weather. Ask for the design forecast and assumptions.
Should a heat pump run continuously?
Many systems work efficiently with long, steady operation and weather compensation rather than short hot bursts. That does not mean maximum output all day. The installer should explain schedules, setback temperatures and how to change comfort without creating inefficient cycling.
Will solar panels run my heat pump?
Solar can offset some electricity, especially for hot water and shoulder-season heating, but winter heat demand rises when solar generation is lower. Model monthly overlap rather than subtracting annual solar generation from annual heat-pump use.
Can I remove the gas standing charge?
Only if no gas appliance remains and the supply is formally closed. If cooking, fires or another appliance still use gas, the charge continues. Include disconnection arrangements and any cost before claiming that saving.
Independent sources
- Energy Saving Trust, Air source heat pumps (accessed 3 October 2026)
- Ofgem, Boiler Upgrade Scheme (accessed 3 October 2026)
- Ofgem, Price-cap unit rates (accessed 3 October 2026)
- MCS, Standards and tools library (accessed 3 October 2026)
Last updated .