How much does an air source heat pump cost to install in the UK? (2026 guide)
Short answer: around £12,500 on average before any grant, according to the latest government Boiler Upgrade Scheme figures. After the £7,500 BUS grant, most homeowners pay somewhere between £3,500 and £6,000. Some smaller properties pay less. Longer answer: it depends on your house, your insulation, your existing radiators, and what the survey turns up. The headline number is a starting point, not a quote. This guide goes through the real numbers, by property size, by what is and is not included, by what adds cost that most installers do not volunteer upfront. There is a West Midlands section near the end with figures specific to Birmingham, Worcester, and the surrounding towns. 2026 cost summary What you pay by property size System size drives most of the price difference. A small flat needs a 5 kW unit. A large detached house might need 14 or 16 kW. That is not just a bigger box, it is more pipework, longer install time, and a higher unit price. These figures cover the heat pump unit, labour, hot water cylinder, standard pipework, and commissioning. Radiator upgrades, electrical work, and other extras are separate, that list comes next. Property System Cost before grant After £7,500 BUS grant VAT saving (0%) 1 to 2 bed flat/house 5 to 7 kW £7,000 to £10,000 £0 to £2,500 ~£350 to £500 2 to 3 bed semi/terrace 7 to 10 kW £9,000 to £12,500 £1,500 to £5,000 ~£450 to £625 3 to 4 bed detached 10 to 13 kW £11,000 to £15,000 £3,500 to £7,500 ~£550 to £750 4 to 5 bed large property 13 to 16 kW £14,000 to £18,000 £6,500 to £10,500 ~£700 to £900 VAT saving calculated at 0% versus 5% standard rate. Relief confirmed until 31 March 2027. Source: HMRC. What Wunergy’s price includes Every installation covers: What is not in that list depends on the property. Older houses usually need more. The extras that catch people out Comparison websites quote national averages. They do not show you what a surveyor finds when they actually walk around your house. These are the most common additions: What Typical cost When it applies Radiator upgrade (per radiator) £150 to £400 Older or undersized rads New hot water cylinder £400 to £900 No cylinder, or current too small Consumer unit upgrade £500 to £1,000 Old electrics that cannot handle load Scaffolding £300 to £600 Unit needs to go high on a wall Pipework changes £200 to £800 Narrow-bore or complex existing pipework Smart controls/thermostat £150 to £400 Recommended on all installs Annual service £150 to £300/yr Every year, keeps warranty valid Watch this when comparing quotes A quote of £8,000 that excludes three radiator upgrades and a new cylinder is not cheaper than a £9,500 quote that includes them. Always ask what is and is not in the price. Wunergy provides a fully itemised quote after the free survey so nothing comes as a surprise later. Why some jobs cost more than others Insulation and heat loss Before any system gets designed, a heat loss calculation works out how much heat your home bleeds on a cold day. Poor insulation means the number is higher, which means a bigger system. A well-insulated three-bed semi typically needs an 8 kW unit. The same house with no loft insulation and single glazing might need 12 kW. That is a difference of roughly £2,000 to £3,000 in unit cost before labour is touched. Radiators Gas boilers push water at 60 to 70 degrees. Heat pumps run at 35 to 50 degrees. Lower flow temperatures mean older radiators often do not give off enough heat, they were sized for the hotter system. Replacing undersized radiators is one of the most common additional costs. Budget £150 to £400 per radiator. A three-bed house typically has seven to nine. Do that maths before dismissing the upgrade. Existing pipework and electrics Narrow-bore pipework in older properties sometimes needs replacing before a heat pump can circulate water properly. Outdated consumer units occasionally need upgrading to handle the additional load. Neither is guaranteed, but both get flagged during a proper survey. Where the unit goes Most outdoor units go on a wall bracket or a small ground pad. Straightforward. But if the best location for airflow means scaffold access or a longer pipe run through the building, that adds to the job. Brand and spec Wunergy fits Samsung units with an ErP A+++ rating. That is the top efficiency band and a requirement to access the Boiler Upgrade Scheme grant. Budget brands exist. Some perform fine. Some do not. The difference shows up in the bills every winter and in how easy it is to get parts if something needs fixing in year eight. Running costs once it is in Electricity is more expensive per unit than gas. That is just the current reality. Ofgem’s April to June 2026 average rates: 24.67p per kWh for electricity, 5.74p per kWh for gas. What changes the picture is efficiency. A heat pump with a COP of 3.0 produces 3 kWh of heat from every 1 kWh of electricity. At 24.67p input, that works out at about 8.2p per kWh of useful heat. A gas boiler at 90 percent efficiency delivers heat at roughly 6.4p per kWh. The gap is smaller than it looks. And it disappears entirely if you are comparing against oil, LPG or electric heating. Heating system Annual running cost vs heat pump Air source heat pump (COP 3.0) £800 to £1,100 Baseline Gas boiler, A-rated new £900 to £1,300 Similar or slightly more Oil boiler £1,400 to £2,000 40 to 80% more LPG boiler £1,600 to £2,200 60 to 100% more Electric storage heaters £2,200 to £3,000 More than double Estimates use Ofgem April to June 2026 price cap and average heating consumption for a 3-bed semi. Real costs vary with insulation quality, system design, and how the thermostat is used. The £7,500 grant: who gets it The Boiler Upgrade Scheme pays £7,500 directly to
Air source vs ground source heat pump: which is right for your home?
People ask this a lot. Usually after a neighbour gets one installed or after opening an energy bill that has gone up again. Both types of heat pump do the same job in broad terms: they take warmth from the environment and use it to heat your home without burning anything. Air source pulls from the air outside. Ground source pulls from the soil below your garden. That difference in where they get their heat shapes everything else about them, including what they cost, how long they take to install, and whether your property can take one at all. For most people reading this in the West Midlands or surrounding areas, the answer is probably an air source heat pump. Not because ground source is bad. It is not. But because it has requirements that most UK properties simply cannot meet. This guide works through those differences properly so you can see which side of the line you fall on. What each system actually does Air source heat pump A fan unit sits outside the building, fixed to a wall or placed on a pad beside the house. It pulls in outside air and passes it across metal fins. Even cold air carries thermal energy. The system extracts that energy, concentrates it using a refrigerant and compressor, and moves it into your home as heat. Inside, it connects to your radiators and a hot water cylinder the same way a boiler would. Day to day, you use it the same way. Set a temperature, the house heats up. Our full guide on how air source heat pumps work covers each stage of the process in detail. Ground source heat pump Instead of the air, a GSHP draws on heat stored underground. A network of pipes, filled with a water and antifreeze mix, gets laid in the garden or drilled vertically into the earth. Below the frost line, ground temperature holds steady at roughly 10 to 13 degrees Celsius all year. That stability is the system’s main advantage over air source. The indoor unit is compact, something like a large fridge freezer, and fits in a utility room. Getting the pipes in the ground is where the time, disruption, and cost all accumulate. The numbers side by side Figures based on UK averages. Your costs depend on property size, insulation level, and whether a borehole is needed. Air source (ASHP) Ground source (GSHP) Installation cost £8,000 to £15,000 £20,000 to £45,000 After £7,500 BUS grant £500 to £7,500 £12,500 to £37,500 Typical COP 2.5 to 4.0 3.0 to 4.5 Space needed Small outdoor area Large garden or borehole Installation time 2 to 3 days 1 to 2 weeks Planning permission Usually not needed Sometimes needed Suitable for flats/terraces Yes Rarely Cold weather efficiency Dips slightly below -10C Stable year-round Lifespan 20 to 25 years 25 years or more Maintenance Annual service Annual service Efficiency: how big is the gap really? Ground source is more efficient. That is not in dispute. The question is how much it matters in practice. Underground temperatures do not change with the seasons. Air temperatures do. On the coldest days of a UK winter, when your heating is working hardest, an air source heat pump is pulling from colder air and has to work harder to produce the same amount of heat. A ground source pump faces no such variation. The numbers from Which? put a typical ASHP at 280 to 380 percent efficiency and a GSHP at 320 to 420 percent. So yes, ground source is better. The gap in real annual bills is usually somewhere between 10 and 20 percent. What softens this considerably is the UK climate. England does not get the kind of sustained deep cold that would push an ASHP into genuinely poor efficiency territory. A few weeks a year, perhaps. The rest of the heating season, the gap between the two systems is fairly small. At -10C, a decent ASHP still produces around 2.5 units of heat per unit of electricity. A gas boiler converts about 90 percent of its fuel at best. The heat pump is still well ahead of the boiler even at its winter low. Cost: where most people make up their mind Air source installations in the UK run from roughly £8,000 to £15,000 before any grant. Ground source starts at around £20,000 and can reach £45,000 or more when a borehole is needed rather than a horizontal ground loop. Both qualify for the £7,500 Boiler Upgrade Scheme grant. After that grant, a smaller ASHP installation can come in below £1,000. A GSHP after the same grant still costs £12,500 at minimum, and often a great deal more. That is a substantial gap. And it does not close quickly through lower running costs. The energy saving from choosing ground source over air source might be a few hundred pounds a year. At that rate, the additional upfront cost takes a very long time to recover. The Energy Saving Trust confirms both pump types receive the same £7,500 grant. The relative affordability of air source only widens once that is factored in. Space: the factor that rules out ground source for most UK homes This is probably the most underappreciated part of the decision. A horizontal ground loop needs roughly 1.5 to 2 times the floor area of the property in clear, unobstructed garden. For a standard three-bedroom semi-detached, that is 200 to 300 square metres. No trees over the pipes. No outbuildings. No services running through. Most UK gardens, particularly in towns and cities, cannot offer that. Boreholes are the alternative when space is tight. The pipes go down vertically rather than spreading horizontally. Problem is, each metre of drilling costs £1,000 to £1,500, heavy equipment has to get to the site, and the process takes days. Boreholes make ground source more accessible but push the cost up further. An air source unit needs a clear metre around it for airflow and a solid wall
How does an air source heat pump work? A beginner’s guide
Most people walk past them every day without noticing them. It’s just a simple box on the side of a house, quietly humming away. That’s an air source heat pump, and right now, it’s one of the most sensible heating upgrades a UK homeowner can make. Gas prices haven’t stabilised, the 2035 boiler phase-out is approaching, and the government grant offering up to £7,500 off installation won’t last forever. So, taking a few minutes to understand how this technology works is well worth your time. In this guide, we’ll cover the basics: what a heat pump does, how it performs in cold weather, what the efficiency numbers really mean, and what the installation process looks like in practice. What is an air source heat pump? At its core, an air source heat pump is a device that moves heat rather than creates it. It pulls warmth from the outside air and transfers it into your home to run your radiators and heat your water. The energy source is electricity, not gas or oil, which is part of why running costs tend to be lower. The comparison most engineers reach for is a refrigerator in reverse. A fridge extracts heat from inside the cabinet and dumps it into your kitchen. A heat pump does the opposite: it pulls heat from the air outside your house and brings it in. Even on a cold January morning, there is usable heat energy in the air. The pump finds it and concentrates it. From a homeowner’s point of view, not much changes day to day. The system connects to existing radiators and a hot water cylinder. You set a temperature. The house heats up. The difference is what is happening behind the scenes. How it works, step by step The process runs in a loop. Once it starts, it keeps going without much input. Step 1: Air is drawn in A fan inside the outdoor unit pulls air across metal fins, similar in principle to the grille at the front of a car. Cold air still holds heat energy. Not much, but enough. The unit is built to extract it. Step 2: The heat moves into a refrigerant The extracted warmth transfers into a refrigerant fluid circulating through the system. This refrigerant has a very low boiling point, so even a modest rise in temperature turns it from liquid into gas. That change of state is what the system relies on. Step 3: The compressor does the heavy lifting The gas gets compressed. This is where the real temperature increase happens. Compressing a gas concentrates its energy and raises its temperature sharply. If you have ever noticed a bicycle pump getting warm during use, the principle is identical. At this stage the refrigerant is hot enough to do useful work. Step 4: The heat transfers into your home The hot gas passes through a heat exchanger, which moves its warmth into the water circulating through your radiators and stored in your hot water cylinder. The heat ends up exactly where you need it. Step 5: Reset and repeat Once the refrigerant has released its heat, it cools back into a liquid and the cycle starts again. The system runs quietly, continuously, with no combustion taking place anywhere in the process. What about cold weather? This is where most people’s scepticism sits, and it is understandable. The idea of extracting useful heat from freezing air sounds counterintuitive. The Samsung units that Wunergy installs are rated to operate at temperatures down to -25 degrees Celsius. The UK very rarely drops below -10. So British winters, even the bad ones, are well inside the working range of these systems. Scandinavia is the practical proof. Norway, Sweden and Finland have colder winters than anything we see here, and they lead Europe in heat pump adoption. This technology was not designed around mild British weather. It was designed for places where winter is genuinely difficult. Performance does ease off a little in extreme cold. At -10 degrees, a good ASHP produces roughly 2.5 units of heat per unit of electricity. A modern gas boiler at peak efficiency converts about 90 to 95 percent of its fuel into heat. The heat pump is still considerably more efficient even at its winter low. COP: the number that explains the savings COP stands for Coefficient of Performance. It is a ratio: heat output divided by electricity input. A gas boiler with 90 percent efficiency has a COP of 0.9. It uses one unit of energy and produces 0.9 units of heat. An air source heat pump with a COP of 3.5 uses one unit of electricity and produces 3.5 units of heat. That gap is why running costs are lower, even accounting for electricity being more expensive per unit than gas. The units Wunergy installs carry an ErP A+++ efficiency rating. That is the highest band available, and it is the rating that confirms eligibility for the Boiler Upgrade Scheme grant. What does an installation involve? A full air source heat pump installation from Wunergy covers everything the system needs to work properly: Most jobs run over two to three days. The Wunergy team handles the whole process from the initial site visit through to final testing and handover. Why the switch makes sense right now Is your home a good candidate? Most UK properties work fine. There are three things worth checking before anything else. If you are not sure whether your property is suitable, Wunergy carries out free surveys across Birmingham, Worcester, Bromsgrove, Redditch, Stratford-upon-Avon and the surrounding areas. You get an honest assessment before any decisions are made. Questions we get asked regularly Can it replace a boiler completely? Yes, in full. The system handles space heating and hot water together, so the boiler comes out and the gas supply can be capped. Nothing needs to stay. My electricity bill, will it go up? It will rise. But the heat output per unit of electricity is three to