How Much Does an Air Source Heat Pump Cost to Run in Wales?
There is no honest one-price-fits-all answer. Running costs depend on the heat your home needs, the system’s seasonal performance, your hot-water use and the electricity tariff you pay. This guide explains how to estimate the cost without relying on unrealistic promises.
Last updated: 11 September 2026. Energy prices, tariffs, VAT and grant rules can change.
The honest short answer
An air source heat pump can be economical to run when it is properly designed for the property, but it is not automatically cheaper than every gas, oil or LPG boiler. Two similar-looking homes can have very different heating costs because of their construction, size, exposure, insulation, indoor temperature and hot-water demand.
That is why a dependable estimate starts with a room-by-room heat-loss calculation and a system design. The price of the outdoor unit alone cannot tell you what the annual bill will be.
Be careful with headline savings. A claim such as “save £1,000 a year” cannot be applied to every home. A fair comparison must use the customer’s actual fuel use, the proposed system performance and the tariff they will genuinely pay.
How running costs are estimated
A heat pump uses electricity to move heat from the outside air into the home. Its seasonal performance factor, often shortened to SPF, describes the relationship between the useful heat delivered over a year and the electricity used by the system over that period.
For example, if a home needs 12,000kWh of useful heat over a year and the complete system achieves a seasonal performance of 3.2, the simplified calculation gives about 3,750kWh of electricity. Multiplying that by the customer’s electricity unit rate gives an indicative cost.
The proper MCS performance estimate is more detailed. It considers space heating and hot water and provides a property-specific estimate of annual energy consumption. It is still an estimate, because weather, occupancy, thermostat settings and actual energy prices will vary.
Three illustrative examples
The examples below use Ofgem’s announced average electricity unit rate of 26.32p/kWh for a Direct Debit customer on a standard variable tariff from 1 October to 31 December 2026. They are simple illustrations, not quotations or performance guarantees.
| Illustrative home | Useful heat needed | Illustrative seasonal performance | Electricity used | Illustrative annual cost |
|---|---|---|---|---|
| Lower heat demand | 8,000kWh | 3.5 | About 2,286kWh | About £602 |
| Medium heat demand | 12,000kWh | 3.2 | About 3,750kWh | About £987 |
| Higher heat demand | 18,000kWh | 3.0 | About 6,000kWh | About £1,579 |
These simplified examples use a blended annual performance figure and exclude the electricity standing charge, which a grid-connected household would normally pay regardless. A full estimate may also account separately for hot water, supplementary heaters, pumps and other system electricity. Your regional rate, payment method and tariff may differ.
What affects a heat pump’s electricity use?
Property heat loss
A larger, draughtier or more exposed home needs more heat. Appropriate insulation and draught reduction can reduce demand, but work should suit the building—especially in older stone properties.
Flow temperature
The greater the temperature lift the heat pump must produce, the harder it works. A well-designed lower-temperature system will normally perform better than one forced to run unnecessarily hot.
Radiators and pipework
Correctly sized emitters help rooms receive the required heat at the chosen flow temperature. This does not mean every radiator must automatically be replaced.
Hot-water demand
The number of occupants, cylinder temperature, shower and bath use, and hot-water schedule all affect consumption. Domestic hot water usually requires a higher temperature than space heating.
Controls and commissioning
Weather compensation, the heating curve, system balancing and sensible thermostat settings all matter. Poor settings can make a good installation use more electricity than necessary.
Your electricity tariff
The same number of kilowatt hours can produce a very different bill on another tariff. A suitable time-of-use or heat-pump tariff may help, but its rules and peak prices must be checked carefully.
You can read more about radiator sizing for heat pumps and whether older and stone homes in Pembrokeshire can be suitable.
How does that compare with oil or LPG?
The fairest comparison uses at least a full year’s fuel bills or delivery records. For oil, that means looking at the litres purchased, the prices actually paid and the likely efficiency of the existing boiler. LPG customers should use their real annual consumption and contract price.
It is misleading to compare one cheap oil delivery with a temporary electricity price, or a new heat pump with a boiler that has not been serviced or is heating the home to a different temperature. Comfort matters too: a household that previously rationed heating may use more energy after the upgrade because the whole home is warmer for longer.
Our guide to oil boilers versus air source heat pumps explains the wider differences, including heating style, fuel storage, radiators, hot water and installation work.
Current electricity prices
From 1 July to 30 September 2026, Ofgem’s Great Britain average Direct Debit price-cap rate is 26.11p/kWh for electricity. From 1 October to 31 December 2026, the announced average is 26.32p/kWh. Regional rates and standing charges differ, and customers on fixed, multi-rate or specialist tariffs may pay something else.
Energy prices change, so a running-cost calculation should show the unit rate and date used. It is also sensible to test more than one price rather than presenting a single forecast as certain.
What grants and VAT relief are available?
The standard Boiler Upgrade Scheme contribution is currently £7,500 towards an eligible air-to-water heat pump. Until 31 March 2027, an additional £1,500 is available where both of these conditions apply:
- The property is currently heated by oil or LPG.
- There is no mains gas connection at the property.
This makes the total contribution £9,000 for a qualifying property; it is not automatically available to every home in Wales. The installation must meet the scheme requirements and the MCS-certified installer applies on the property owner’s behalf.
Qualifying residential air source heat pump installations are also currently zero-rated for VAT until 31 March 2027. Grant rules and tax treatment can change, so both should be confirmed when the quotation is prepared.
What you receive after a proper survey
Del Brace Plumbing & Heating’s heat-pump survey costs £375 including VAT and usually takes between one and three hours. The survey fee is deducted if you proceed with the installation.
The assessment gives the information needed to move from a rough online example to a property-specific proposal, including:
- Room-by-room heat-loss calculations.
- Proposed heat-pump size and design conditions.
- Radiator, underfloor-heating and pipework assessment.
- Hot-water cylinder and household demand assessment.
- Expected seasonal performance and annual electricity consumption.
- Electrical supply, outdoor position and practical installation requirements.
- Boiler Upgrade Scheme eligibility checks.
See exactly what happens during a heat-pump survey before deciding whether to book.
Heat pump running-cost questions
Will a heat pump definitely reduce my bills?
No installer should guarantee that from the technology alone. The result depends on your current fuel cost and boiler efficiency, the home’s heat demand, the heat pump’s seasonal performance, controls, hot-water use and electricity tariff.
Does a heat pump need to run all the time?
Heat pumps normally operate for longer, steadier periods than boilers, often using weather compensation to match the home’s heat loss. That does not mean the compressor must run continuously. The controls should be commissioned for the property rather than copied from another home.
Do larger radiators reduce running costs?
Correctly sized radiators can deliver the required room heat at a lower water temperature, which can improve heat-pump performance. They should be selected from the room heat-loss calculation; replacing every radiator without calculating the requirement is unnecessary.
Will solar panels run my heat pump for free?
Solar PV can offset part of a home’s electricity use, but solar output is usually lowest during the coldest, darkest part of winter when heating demand is highest. The benefit depends on the size of the array, household use, controls, tariff and any battery storage.
Is a specialist heat-pump tariff always cheaper?
Not always. Some tariffs offer cheaper periods or a discounted rate for heat-pump consumption, but may have eligibility rules, peak rates or smart-meter requirements. Compare the whole tariff against the times your household actually uses electricity.
Can you estimate costs without visiting?
A rough illustration may be possible from past energy use, but a dependable proposal requires the property’s dimensions, construction, ventilation, emitters, hot-water demand and design temperatures to be assessed.
Local design, installation and aftercare
Del Brace Plumbing & Heating designs and installs MCS-certified air-to-water heat-pump systems across Pembrokeshire, including Tenby, Saundersfoot, Kilgetty, Narberth, Pembroke, Pembroke Dock and Whitland.
- MCS registration APH48084
- Worcester Bosch Accredited Installer
- TrustMark approved
- RECC and APHC member
- Room-by-room system design
- Local servicing and aftercare
Explore our air source heat pump service or browse more helpful heat-pump guides for Pembrokeshire homeowners.
Official information used in this guide
Current information was checked against GOV.UK Boiler Upgrade Scheme guidance, Ofgem’s guidance for property owners, HMRC VAT Notice 708/6 and MCS 031 performance-estimate guidance.
