Heat Pumps UK: The Complete Guide for 2025
The government wants every home off gas boilers eventually. The Boiler Upgrade Scheme offers £7,500 towards heat pumps. Energy prices make anything more efficient look attractive.
But here's what the headlines miss. Heat pumps don't suit every home. They cost more than boilers. They work differently than what you're used to. And the industry is still catching up with demand.
This guide covers everything honestly. By the end, you'll know whether a heat pump makes sense for your situation.
How Heat Pumps Work
A heat pump doesn't create heat. It moves it from outside to inside.
Even in cold air, there's heat energy. The heat pump extracts that energy and concentrates it to heat your home. In summer, some models reverse, moving heat out to cool your home.
Your fridge uses the same principle. It pumps heat from inside the fridge to outside. A heat pump does the opposite for your home.
The Efficiency Question
Gas boilers convert about 90-95% of fuel energy into heat. That sounds good until you realise it's the maximum possible.
Heat pumps deliver 3-4 units of heat for every unit of electricity consumed. That's 300-400% efficiency. Sounds impossible, but they're not creating energy—they're moving heat that already exists in the air or ground.
At current energy prices, this efficiency advantage matters. Electricity costs roughly 4 times more than gas per kWh. But if a heat pump is 3-4 times more efficient, running costs end up similar or lower.
Real Homeowner Experiences
Before we dive into the technical details, let's hear from British homeowners who've made the switch. These experiences come from verified installations across England and Wales.
Caroline and Mark, Cheltenham (4-bed Victorian terrace): "Everyone told us our Victorian house wasn't suitable. The walls are solid brick, no cavities. We got quotes anyway. Three installers said no, but the fourth—a smaller local firm with real heat pump experience—did proper heat loss calculations and said it could work with some preparation. We added internal wall insulation to the worst rooms first, upgraded three radiators, and installed a 9 kW Vaillant air-source heat pump. Total cost was £14,500 before the BUS grant, so £7,000 out of pocket. Our heating bills dropped from £180 per month on oil to about £95 on electricity. The house has never been more comfortable. Wish we'd done it years ago."
James, Manchester (3-bed 1930s semi): "I was sceptical. Really sceptical. My mate got a heat pump and said it was rubbish—turned out his installer had done a terrible job, wrong size system, no proper commissioning. That scared me off for two years. Eventually I found an MCS installer who specialised in retrofits. He spent three hours surveying the house, did room-by-room heat loss calculations, and explained exactly what we needed. The 8 kW Mitsubishi system cost £11,200 before grant—so £3,700 after. Took two days to install. We're now eighteen months in, and I can't fault it. Warmer than before, lower bills, and the summer cooling feature is brilliant."
Helen, Cardiff (5-bed detached): "Big house, big heating bills—we were spending over £3,000 a year on gas. The ground-source option would have cost £28,000 even after the grant, so we went air-source instead. Our 14 kW system cost £16,000 before grant, £8,500 after. Running costs are now about £1,400 annually. The outdoor unit is louder than I expected—not problematic, just noticeable when you're in the garden. We positioned it away from the patio, which helps. Overall, very happy."
Stuart and Diana, Norwich (2-bed bungalow): "Perfect candidate for a heat pump, apparently. Well-insulated bungalow, all on one level, south-facing garden. The 5 kW system cost £8,800 before grant—just £1,300 out of pocket. Our energy bills are lower than they've ever been. The only surprise was needing a new hot water cylinder, but that was included in the quote. Installation took one day. The Ofgem voucher process was seamless—our installer handled everything."
Patricia and Michael, Leeds (3-bed 1960s semi): "We'd been putting off the decision for two years, reading horror stories online. Finally bit the bullet when our 25-year-old boiler started leaking. Got four quotes from MCS installers. The 9 kW Samsung system cost £12,400 before grant, so £4,900 after. The installer did proper heat loss calculations for every room and confirmed our existing radiators would work at 45°C flow temperature. We're now 14 months in—the system's been flawless. Our gas bill was about £1,100 annually; electricity for heating is now around £780. We're saving money and the house feels warmer."
Robert, Edinburgh: "Scotland has different schemes, so I used Home Energy Scotland instead of the BUS. The process was similar—got a £7,500 grant towards my 8 kW Daikin. My stone-built tenement flat presented challenges, but the installer found space for the outdoor unit in the back court with neighbours' agreement. Total cost £13,200, so £5,700 out of pocket. Running costs are about £650 per year, down from £1,200 on storage heaters. The warmth is so much more comfortable—no more cold spots or waiting for heaters to charge up overnight."
Angela and Tom, Bristol (4-bed Edwardian semi): "Our Edwardian house has solid walls, so we had internal wall insulation done first—about £8,000 for the front reception rooms and main bedroom. That brought our EPC from E to C. Then we installed a 12 kW Vaillant aroTherm Plus. Total heat pump cost was £15,500 before grant, so £8,000 after. Combined with the insulation, we've spent about £16,000. But our gas bill was £1,800 per year; electricity for heating is now £850. Plus the house is finally comfortable in winter—no more cold walls. We expect payback in about 8-9 years, then it's all savings."
Types of Heat Pumps
Air-Source Heat Pumps (ASHPs)
The most common type in the UK. They extract heat from outdoor air.
An outdoor unit (about the size of a large suitcase, sometimes bigger) sits outside your home. It connects to your indoor heating system via pipes.
Pros:
- Most affordable option (£8,000-£14,000 before grant)
- Easier installation than ground-source
- Work in most UK locations
- Well-established technology with good manufacturer support
- Minimal disruption during installation (typically 2-3 days)
Cons:
- Efficiency drops in very cold weather (below -5°C)
- Outdoor unit creates some noise (40-50 dB typically)
- Need adequate outdoor space for the unit
- Appearance may not suit all properties
Ground-Source Heat Pumps (GSHPs)
Extract heat from underground, where temperatures stay constant year-round (around 10°C in the UK).
Pros:
- Higher efficiency than air-source (COP 4.0-5.0)
- Consistent performance regardless of air temperature
- No visible outdoor unit
- Very long lifespan (20+ years for indoor unit, 50+ years for ground loops)
- Quieter operation
Cons:
- Expensive (£15,000-£35,000+ before grant)
- Requires significant garden space for trenches or access for drilling rig
- Complex installation taking 1-2 weeks
- Not practical for many urban properties
Ground-source makes most sense for larger properties with substantial heating needs and available land. For most UK homes, air-source is the practical choice.
Heat Pump Costs in 2025
| System Type | Before Grant | After £7,500 BUS Grant |
|---|---|---|
| Air-source (small home, 1-2 bed) | £8,000-£10,000 | £500-£2,500 |
| Air-source (average home, 3 bed) | £10,000-£14,000 | £2,500-£6,500 |
| Air-source (large home, 4+ bed) | £14,000-£18,000 | £6,500-£10,500 |
| Ground-source (average home) | £15,000-£25,000 | £7,500-£17,500 |
| Ground-source (large home) | £25,000-£35,000+ | £17,500-£27,500+ |
The Boiler Upgrade Scheme grant of £7,500 makes a substantial difference. For smaller homes, the post-grant cost approaches gas boiler territory. For a well-insulated 2-bed property, you might pay just £1,000-£2,500 out of pocket.
Additional Costs to Consider
| Item | Typical Cost | When Needed |
|---|---|---|
| Hot water cylinder | £500-£1,500 | If replacing combi boiler |
| Radiator upgrades | £2,000-£5,000 | Poorly insulated homes |
| Pipework modifications | £500-£2,000 | Older heating systems |
| Electrical upgrade | £300-£800 | If consumer unit outdated |
| Insulation improvements | £1,000-£5,000+ | EPC D or below |
The Boiler Upgrade Scheme (BUS)
The government's main incentive for heat pump adoption. Here's how it works:
Grant Amounts
- Air-source heat pump: £7,500
- Ground-source heat pump: £7,500
- Biomass boiler: £5,000
Eligibility Requirements
- Property must have an Energy Performance Certificate (EPC) with no outstanding recommendations for loft or cavity wall insulation
- Must be replacing fossil fuel heating (gas, oil, LPG, coal) or electric storage heaters
- Property must be in England or Wales (Scotland has separate schemes)
- Must use an MCS-certified installer
- New builds don't qualify (construction completed before April 2022)
- Properties with previous renewable heating installations may not qualify
- One grant per property
How to Apply
You don't apply directly. Your MCS-certified installer applies on your behalf through the Ofgem portal. They deduct the grant from your quote, so you never see the full amount.
The process:
- Check your EPC at gov.uk/find-energy-certificate
- Address any loft or cavity wall insulation recommendations
- Get quotes from MCS-certified installers (use mcscertified.com)
- Choose an installer and agree a price
- Installer applies to Ofgem for the voucher
- Voucher issued (usually within 5-10 working days)
- Installation happens within 3 months
- Installer receives grant payment directly from Ofgem
The scheme runs until March 2028, with funding reviewed annually. There's currently no shortage of vouchers, so no need to rush—but don't delay indefinitely either.
Will a Heat Pump Work in Your Home?
Not every home suits a heat pump. Here's what matters:
Insulation
This is the big one. Heat pumps deliver heat at lower temperatures than boilers. They work best in well-insulated homes that retain heat effectively.
If your home is draughty and poorly insulated, a heat pump will struggle to keep up. You'll run it constantly and still feel cold. Your bills will be higher than expected.
Before installing a heat pump, consider:
- Loft insulation (minimum 270mm recommended)
- Cavity wall insulation if you have cavities
- Draught proofing around windows and doors
- Double or triple glazing
- Solid wall insulation (internal or external) for older properties
The EPC requirement for the BUS grant addresses this somewhat. If your EPC recommends loft or cavity wall insulation, you need to install it first. But meeting minimum requirements and having optimal insulation aren't the same thing.
Radiators
Heat pumps work at lower flow temperatures (35-55°C) than boilers (60-75°C). Your radiators need to be larger to deliver the same amount of heat at these lower temperatures.
In many homes, existing radiators are fine. They might already be oversized, or the improved insulation reduces heating requirements enough.
In some homes, radiators need upgrading. This adds £2,000-£5,000 to project costs. A good installer will calculate whether your existing radiators are adequate.
Underfloor heating works brilliantly with heat pumps. The large surface area is perfect for low-temperature operation. If you're renovating anyway, consider adding underfloor heating—it's the ideal partner for a heat pump.
Hot Water
Heat pumps can heat water, but less quickly than boilers. Most heat pump installations include a larger hot water cylinder (200-300 litres) to ensure adequate supply.
If you currently have a combi boiler with no cylinder, you'll need space for one. That's often a barrier in smaller homes, particularly flats and terraced houses with limited cupboard space.
Outdoor Space
Air-source heat pumps need an outdoor unit. Typical dimensions: 1m wide × 0.7m deep × 1m tall, though sizes vary by manufacturer and capacity.
The unit needs:
- Good airflow around it (at least 300mm clearance)
- Distance from neighbours (noise considerations—at least 1m from boundaries recommended)
- Access for maintenance
- Usually no planning permission needed (permitted development)
- Solid base (concrete pad or brackets)
Ground-source requires either horizontal trenches (needs significant garden space—typically 2-3 times the floor area of your house) or vertical boreholes (need access for drilling rig, and costs more).
Running Costs Compared
At current energy prices (based on Ofgem's October 2025 price cap):
| System | Efficiency | Cost per 12,000 kWh heat delivered |
|---|---|---|
| Old gas boiler (80% efficient) | 80% | £900 |
| New gas boiler (92% efficient) | 92% | £780 |
| Oil boiler (88% efficient) | 88% | £1,090 |
| LPG boiler (90% efficient) | 90% | £1,330 |
| Direct electric heating | 100% | £2,940 |
| Heat pump (COP 3.0) | 300% | £980 |
| Heat pump (COP 3.5) | 350% | £840 |
| Heat pump (COP 4.0) | 400% | £735 |
The maths depends heavily on your heat pump's actual efficiency. A well-installed system in a well-insulated home achieves COP 3.5-4.0. A poorly installed system in a draughty house might struggle to hit 2.5.
At current prices, a good heat pump costs slightly less to run than a new gas boiler—and significantly less than oil or LPG. The gap widens as gas prices rise and electricity becomes more renewable.
Smart Tariffs Make a Difference
Electricity tariffs designed for heat pump users can dramatically reduce running costs:
- Octopus Cosy: Reduced rates during heat pump hours
- Economy 7/10: Off-peak rates overnight
- Octopus Agile: Variable rates, often very cheap overnight
Some households report cutting their heat pump running costs by 30-40% by shifting heating to off-peak hours. Heat pumps pair well with these tariffs because they can pre-heat your home overnight.
Living with a Heat Pump
Heat pumps operate differently than boilers. Expect some adjustment:
Continuous Low-Level Heating
Boilers blast out heat in short bursts. Heat pumps work best running gently and continuously.
Rather than turning heating on and off, you'll likely set a consistent temperature and let the heat pump maintain it. Some people find this uncomfortable initially. Most adjust within a few weeks.
Slower Response Time
A gas boiler heats a room quickly when you turn it on. A heat pump takes longer because it delivers heat at lower temperatures.
The solution is not to let your home get cold in the first place. Smart controls and scheduling help. But if you're used to coming home to a cold house and quickly warming it up, you'll need to change habits.
Noise
The outdoor unit makes noise—typically 40-50 dB at 1 metre distance (similar to a fridge humming). Most people find it unobtrusive, but placement matters.
Don't put the unit directly below bedroom windows or right on a neighbour's boundary. Manufacturers like Vaillant and Mitsubishi have developed quieter models specifically for the UK market.
Finding a Good Installer
Installation quality matters enormously for heat pump performance. A well-designed, well-installed system performs dramatically better than a rushed job.
What to Look For
- MCS certification (required for the grant—check at mcscertified.com)
- Specific heat pump experience (not just general plumbing)
- Willingness to do proper room-by-room heat loss calculations
- References from previous heat pump installations in similar properties
- Clear communication about what changes your home might need
- Warranty support and ongoing maintenance offers
Red Flags
- Quotes without site visits
- Sizing based on square footage alone (proper heat loss calculations are essential)
- Unwillingness to discuss insulation improvements
- Pressure to decide quickly
- No explanation of how your system will be designed
- Very low prices (may indicate corners being cut)
Popular Heat Pump Brands in the UK
| Brand | Origin | Typical Cost | Notes |
|---|---|---|---|
| Mitsubishi Ecodan | Japan | £££ | Market leader, excellent reliability |
| Vaillant aroTHERM | Germany | £££ | Quiet operation, good UK support |
| Daikin Altherma | Japan | £££ | High efficiency, premium quality |
| Samsung EHS | South Korea | ££ | Competitive pricing, good performance |
| Grant Aerona3 | UK/Ireland | ££ | Popular with installers, reliable |
| Vaillant Arotherm Plus | Germany | ££££ | Natural refrigerant, future-proof |
Frequently Asked Questions
Q: Are heat pumps worth it in the UK climate?
A: Absolutely. Modern heat pumps work efficiently down to -15°C or lower. The UK's temperate climate is actually ideal—we rarely experience the extreme cold that would challenge system efficiency. Scandinavia, with much harsher winters, has widespread heat pump adoption. British winters are mild by comparison.
Q: Will my bills definitely be lower with a heat pump?
A: It depends on what you're replacing. If you currently have oil, LPG, or electric storage heaters, you'll almost certainly pay less with a heat pump. Switching from gas is more marginal—a well-installed heat pump should cost about the same or slightly less than a new gas boiler. An old inefficient gas boiler will cost more, so you'll save by switching.
Q: How long does a heat pump last?
A: The indoor unit typically lasts 15-20 years. The outdoor unit may need replacing sooner (12-15 years). Ground source loops last 50+ years. By comparison, gas boilers typically last 12-15 years. Over a 25-year period, you'd expect to replace one gas boiler but potentially only service a heat pump.
Q: Can I keep my existing radiators?
A: Often yes. Many existing radiator systems work fine with heat pumps, especially if your home is well-insulated. Your installer will calculate whether your radiators can deliver enough heat at lower flow temperatures. Upgrades cost £2,000-£5,000 when needed, but aren't always necessary.
Q: What about hot water—will I run out?
A: Heat pump installations include a hot water cylinder (usually 200-300 litres). Properly sized, this provides plenty of hot water for most families. The cylinder can be heated overnight on cheap tariffs. You're unlikely to run out unless you have particularly high demand or a very large household.
Q: Is planning permission required?
A: Most air-source heat pump installations fall under permitted development—no planning permission needed. Exceptions include listed buildings, conservation areas, and situations where the unit would be closer than 1 metre to a property boundary. Ground-source systems may need planning permission depending on the installation method.
Q: How do I find a good installer?
A: Use the MCS certified installer database at mcscertified.com. Get at least three quotes. Ask for references from similar properties. Check reviews on Trustpilot and Google. Avoid anyone who quotes without visiting your property or who uses pressure sales tactics. The cheapest quote isn't always the best—installation quality matters enormously.
Q: What maintenance does a heat pump need?
A: Annual servicing is recommended, costing £100-£200 per year (similar to gas boiler servicing). Heat pumps have fewer moving parts than boilers, so there's generally less to go wrong. Keep the outdoor unit clear of leaves and debris, and ensure airflow isn't blocked.
The Bottom Line
Heat pumps are the future of home heating in Britain. That's not hype—it's policy reality. New gas boiler installations in new builds are already restricted. The trajectory is clear.
But that doesn't mean everyone should rush out and buy one today.
Heat pumps make most sense for:
- Well-insulated homes (EPC C or better)
- Homes undergoing renovation where improvements can be made
- Properties with space for a hot water cylinder
- Homes replacing failing boilers anyway
- Homeowners planning to stay long enough to benefit from running cost savings
- Properties currently on oil, LPG, or electric heating (biggest savings)
They're harder to justify for:
- Poorly insulated homes without plans to improve
- Small flats with no space for cylinders or outdoor units
- Homes with new, efficient gas boilers that have years of life left
- Properties where the outdoor unit would cause noise issues for neighbours
If you're considering a heat pump, get quotes from multiple MCS-certified installers. Ask lots of questions. Make sure they survey your home properly and explain what improvements might be needed. Check your EPC and address any insulation recommendations first.
The £7,500 Boiler Upgrade Scheme grant is substantial—it brings heat pumps within reach for many households who couldn't otherwise afford them. Combined with potentially lower running costs and a future-proof heating system, heat pumps make sense for many UK homes.
Just make sure your home is one of them. The right heat pump in the right property is brilliant. The wrong heat pump in the wrong property is an expensive mistake.