A typical air source heat pump costs between £550 and £1,200 per year to run for a three-bedroom home, depending on your electricity tariff and the heat pump’s efficiency (SPF). The Energy Saving Trust estimates an average running cost of around £800 per year for a well-sized system in a typical semi-detached property (Energy Saving Trust, 2026).
- Average annual cost is £800 for a three-bed semi-detached home.
- Heat pump running costs are 20–40% lower than a gas boiler.
- Insulation and a high SPF (4.0+) cut costs to £720 or less.
The exact figure depends on your home’s heat demand, the heat pump’s Seasonal Performance Factor (SPF), and your electricity rate. A typical SPF of 3.0 means the pump delivers 3 kWh of heat for every 1 kWh of electricity used. Homes with poor insulation or larger floor areas will see higher costs. The running cost is usually 20–40% lower than a modern gas boiler, but gas prices are lower per kWh, so savings depend on your tariff and SPF.
Heat pump running cost compared to a gas boiler
A gas boiler costs roughly £700–£1,100 per year to run for a three-bedroom home, based on Ofgem’s typical gas usage of 12,000 kWh and a price cap of 6.5p per kWh (Ofgem, 2026). A heat pump with an SPF of 3.0 using electricity at 24p per kWh costs around £960 for the same heat output. However, homes with a high SPF (4.0 or more) can cut costs to £720 or less, making the heat pump cheaper to run. The gap narrows if you have a time-of-use tariff, such as Economy 7 or a smart tariff, which can reduce electricity rates to 15p per kWh overnight.
Key factors that affect your heat pump running cost
Your home’s insulation level is the biggest variable. A well-insulated property with double glazing and loft insulation may need only 6,000–8,000 kWh of heat per year, while a draughty Victorian house could need 15,000 kWh or more. The heat pump’s SPF also matters: a modern unit with an SPF of 3.5 uses 35% less electricity than one with an SPF of 2.5. The Energy Saving Trust notes that proper sizing and installation by an MCS-certified installer can improve SPF by up to 20% (MCS, 2026).
How to reduce your heat pump running cost
Switch to a heat-pump-optimised electricity tariff, such as Octopus Cosy or EDF’s Heat Pump tariff, which can offer rates below 20p per kWh during peak heating hours. Set your flow temperature to 35–40°C rather than 50–55°C — this can boost SPF by 10–15%. The UK government’s Boiler Upgrade Scheme provides a £7,500 grant towards installation, but running cost savings depend on your energy supplier and usage patterns (GOV.UK, 2026). Regular servicing and keeping the outdoor unit clear of debris also maintain efficiency.
A worked example
For a 1930s semi-detached house in Manchester with a 10 kW heat pump and an SPF of 3.5, the annual running cost is roughly £685 on a standard variable tariff at 24p per kWh. This home uses 10,000 kWh of heat per year, so the heat pump consumes 2,857 kWh of electricity. The Energy Saving Trust confirms that a well-insulated home with loft and cavity wall insulation can cut this figure by up to 20%. With the 0% VAT rate on heat pumps until March 2027, the upfront cost after the BUS grant of £7,500 is approximately £3,500 for a typical installation. Over 25 years, the total savings compared to a gas boiler amount to around £6,250, assuming gas prices stay near 6.5p per kWh. The payback period on the net investment is roughly 6 years when you factor in the lower running costs.
| Item | Figure |
|---|---|
| Upfront cost after grants | £3,500 |
| Yearly savings | £250 |
| Payback period | 6 years |
| 25-year lifetime savings | £6,250 |
What homeowners often get wrong
The most common mistake is assuming heat pumps cost the same to run as a gas boiler without checking your home’s insulation first. Here are three frequent errors that can inflate your bills.
- Skipping insulation upgrades Installing a heat pump in a draughty home with single glazing forces the system to work harder, raising running costs by up to 40%. The right approach is to insulate your loft and walls first, which Energy Saving Trust says can cut heat demand by a third and bring your heat pump cost down to under £600 per year.
- Ignoring time-of-use tariffs Running the heat pump on a standard flat-rate electricity tariff misses the chance to save up to £150 annually. Switching to an Economy 7 or Octopus Agile tariff lets you heat your home during cheaper off-peak hours, reducing the per-kWh cost from 24p to as low as 12p.
- Choosing the wrong size heat pump Oversizing the unit by 2 kW or more adds £100–£200 to yearly running costs because the system short-cycles and loses efficiency. A proper heat loss calculation by an MCS-certified installer ensures the pump matches your home’s exact demand, keeping the SPF above 3.5 and your bills low.
Quick reference
- A heat pump with an SPF of 4.0 costs about £600 per year to run for a three-bed semi-detached home using 10,000 kWh of heat.
- Installing a heat pump in a home with no loft insulation can double your annual running cost from £800 to over £1,600.
- You must have an EPC rating of D or better to qualify for the BUS grant of £7,500 towards installation costs.
- Switching from a gas boiler to a heat pump with a time-of-use tariff can save you up to £300 per year on heating bills.
- Running a heat pump on a standard tariff without checking your SPF risks voiding your warranty if the system underperforms.
Frequently Asked Questions
Between £46 and £100 per month for a three-bedroom home. The Energy Saving Trust says a typical semi-detached property costs about £67 per month, depending on your electricity tariff and the heat pump's SPF.
Yes, in many cases. A heat pump with an SPF of 3.0 costs around £960 per year, while a gas boiler costs £700–£1,100, but homes with an SPF of 4.0 or more can see costs drop to £720, making the heat pump cheaper overall according to Ofgem data.
Your home's insulation level is the biggest factor. The Energy Saving Trust states that a well-insulated home reduces heat demand significantly, followed by the heat pump's SPF and your electricity rate, especially with time-of-use tariffs like Economy 7.
