Heat Pumps FAQ

Yes. Modern heat pumps operate down to -25°C outside, and most still deliver full rated output at -10°C. Typical UK winters sit between 0°C and 5°C, so the unit spends most of the year well inside its comfortable range.

Efficiency does dip on the coldest days, that's normal physics, but a properly sized system is designed around peak demand at the coldest temperature your area sees. So when a real cold snap hits, the heat pump still keeps up.

A gas boiler delivers roughly 90% efficiency; about 10% is lost up the flue. A heat pump moves heat from outside air, so for every 1 unit of electricity it draws you get back 3 to 5 units of heat. Lower flow temperatures run more efficiently: 35°C beats 55°C. Check any model's SCOP in the MCS Product Directory; pairing with solar or a smart tariff stretches savings further.

Around 15 to 20 years for a well-maintained air source heat pump, broadly similar to a gas boiler. Ground source loops can last 50+ years, though the indoor unit still needs replacing on a 20-year cycle. Correct sizing, sensible flow temperatures, and an annual service matter most. Run it hot constantly and you shorten its life; steady lower temperatures help components last longer.

SCOP stands for Seasonal Coefficient of Performance: the real-world average efficiency across a full year, including cold winters and milder shoulder seasons. A SCOP of 3.5 means 3.5 units of heat per unit of electricity. Typical UK installs land between 3.0 and 4.5. Lower flow temperatures, good insulation, and correct sizing push it up, and SCOP is what drives your running costs.

Yes, an annual service is sensible, much like a boiler. The service covers a system pressure check, electrical connections, refrigerant condition, control settings, and a clean of the outdoor unit's coil and fan if there's debris on it.

It usually takes under an hour and keeps the manufacturer warranty valid. Skipping services can shorten the lifespan of the unit, especially the compressor, which is the most expensive component to replace.

The Boiler Upgrade Scheme pays up to £7,500 toward an eligible air source heat pump in England and Wales when you replace fossil fuel or electric heating and meet the published rules. The grant comes off your total cost upfront, before any finance is applied, not as a rebate later. Eligibility depends on your property, your EPC, and your existing heating system, all of which we check during the survey before submitting the application for you.

Yes, your electricity bill rises, but your overall heating bill usually falls. A heat pump returns 3 to 5 units of heat for every unit of electricity, so total energy cost is lower than gas or oil. Savings depend on SCOP, insulation, and your tariff. A heat-pump-friendly overnight rate and solar help. See our running costs guide.

No, but it covers a meaningful chunk. The Boiler Upgrade Scheme pays up to £7,500 for eligible installs. A typical fully fitted system costs more than that, with the exact figure depending on your home's size, radiators, and pipework.

Your installer applies the grant directly off the price before you pay anything, so you never have to claim it back yourself.

Savings typically land between 10% and 40% on annual heating versus a gas boiler. Three things drive the range: your SCOP (usually 3.0 to 4.5), insulation, and electricity tariff. Well-insulated homes with sensible flow temperatures and a heat-pump tariff sit at the top; oil or LPG homes often save more. Our running costs guide walks through the numbers.

Around £11,000 is the typical UK installation cost before support, according to the Energy Saving Trust. The £7,500 Boiler Upgrade Scheme grant comes straight off that, so most eligible installs land well below the headline figure depending on the home and any radiator work. Get a fixed figure for your home through our online quote.

No, not in normal use. Manufacturer-published sound pressure for the air-to-water models we install is typically 25-38 dB(A) at 3 metres on low load (Samsung Gen 7 R290 in Quiet Mode sits in the high 20s at 3 m, Vaillant aroTHERM plus 5 kW at 36 dB(A)). Your install needs an MCS noise assessment for permitted development, which we run before booking. See our MCS 020 guide and the ruler on our heat pumps page.

Usually no. Heat pumps run cooler than a boiler, around 35°C to 45°C at the radiators instead of 60°C+. That means each radiator has to be big enough to heat its room at the lower temperature. Some already are. Some need swapping for a bigger panel.

In practice, most homes keep most of their radiators. A heat loss survey goes room by room and tells you exactly which ones need to change before anything gets ordered.

Around two weeks from quote to install. The fitting itself takes 2 to 4 days on site. A straight swap where your radiators are already compatible sits at the shorter end. If you need a new hot water cylinder, larger radiators, or extra pipework, it stretches to the full four days. Your heating is off briefly during the changeover, and you'll have hot water back before the end of the day.

Usually not. Most domestic heat pump installs count as permitted development in England, Scotland and Wales, so no planning application is needed. There are conditions on the unit's size, position, and noise that vary slightly by nation, and listed buildings or conservation areas always need separate consent.

Since 28 May 2026, MCS 020 a) is the only certification route for permitted development in England. We'll assess your specific property during the design stage and let you know what applies.

Less than most expect. Most installs take 2 to 4 days: engineers work outside for the unit and inside for the cylinder, pipework, and controls. Heating is off briefly during changeover; hot water is usually back the same day the boiler comes out. No major building work or whole-house rewiring, and we protect floors and clear up daily.

Yes, with air-to-water heat pumps. They heat water at a lower temperature than a combi, so hot water is stored in a cylinder rather than fired on demand. Most homes use the airing cupboard. If you have a combi and no cylinder, your installer fits one: typically 180 to 250 litres for a family home. Your survey confirms size and location before ordering.

Domestic air source heat pumps run from 3.5 kW to 16 kW. The right size depends on heat loss: floor area, insulation, glazing, and your area's coldest typical temperature. A well-insulated 3-bed semi usually lands between 6 and 10 kW. Oversizing causes cycling and inefficiency; undersizing means struggling on cold days. A heat loss survey pins the number before anything gets ordered.

A few practical things matter: reasonable insulation (cavity walls and loft as a minimum), outdoor space for the unit (roughly 1.3 m by 0.5 m), room for a hot water cylinder if you don't have one, and radiators sized for lower flow temperatures. A proper survey looks at all of that and gives you a clear answer before you commit.

Possible, but harder than a house. The outdoor unit needs a balcony, external wall, or shared plant area, which usually means freeholder or management consent. Leaseholders nearly always need landlord permission. Planning rules are stricter for flats, so noise and siting get scrutinised closely. If the building has communal heating, a building-wide upgrade may suit better than a flat-by-flat retrofit.

Yes, for most homes with reasonable insulation. An air source heat pump delivers 3 to 4 units of heat per unit of electricity, the £7,500 Boiler Upgrade Scheme grant closes most of the upfront gap with a boiler, and running costs beat gas on a heat pump tariff. The honest caveats: savings depend on your insulation, your tariff, and a properly sized install.

The main downsides are higher upfront cost, the space the system needs, and savings that depend on your home. Upfront cost is higher than a boiler before the £7,500 BUS grant. You need outdoor space for the unit and indoor space for a hot water cylinder. Some homes need a few radiators upsized. And because it runs on electricity, savings depend on your tariff and insulation. For most UK homes, none of these outweigh the running-cost gains.

Yes. A hybrid setup runs the heat pump most of the time and brings the boiler in during the coldest snaps or for quick hot water top-ups. Some heat pump models come with a hybrid kit for exactly this. Most households find the boiler barely fires once they're used to the heat pump, but it's there if you're not ready for a full switch.

Air source suits most UK homes: the unit sits outside on a slab and costs less to install. Ground source is more efficient (SCOP often 4.0 to 5.0 versus 3.0 to 4.5 for air) because ground temperatures stay stable, but it needs land for trenches or boreholes and costs significantly more. Air source wins on practicality for typical plots; ground source suits larger sites or off-grid homes where running costs must stay minimal.

Air-to-water heat pumps heat the water in your radiators and hot water cylinder, covering central heating and hot water. Most UK homes install this type, and it qualifies for the full £7,500 Boiler Upgrade Scheme grant. Air-to-air units push warm air through indoor units like air conditioning: they heat rooms but not hot water, so you keep a separate hot water source. UKEM installs air-to-water systems only.

Yes. Most homeowners choose to spread the cost over several years rather than pay upfront, and finance options are available alongside the Boiler Upgrade Scheme grant. The grant comes off the headline price first, and the finance covers what's left.

Monthly payments depend on the term you pick, the amount financed, and your circumstances. We'll talk you through the options on your quote so you can compare upfront and monthly costs side by side before deciding.

Yes, the two stack. The Boiler Upgrade Scheme grant of up to £7,500 comes off the headline install price first. Your finance agreement then covers what's left after the grant, not the full sticker price.

That means smaller monthly payments than you'd see without the grant. We confirm grant eligibility during the survey and apply it before any finance figures get quoted on your heat pump proposal.

Yes, when you apply. Getting a heat pump price does not touch your credit file. Applying for finance does: it runs a full credit check recorded on your file. You can apply online for an immediate decision, or we take you through it, so the check only happens once you choose to proceed. See our finance page for how it works.

Yes. UK consumer finance agreements let you settle early at any point, and most lenders waive or reduce remaining interest when you do. Request a settlement figure from the lender, pay it, and the agreement closes. Some include a small early settlement adjustment capped under the Consumer Credit Act; partial overpayments and full settlement are both standard options.

Heat pump finance is arranged through FCA-authorised lenders who specialise in home improvement and renewable energy installs. We act as a credit broker, not the lender itself, and we're authorised and regulated by the Financial Conduct Authority for that role.

The lender carries out the credit assessment and holds the agreement. We handle the paperwork, the grant claim, and the install. See our finance page for the full regulatory disclosure.

Not always. Some agreements run with no deposit at all, and others let you put down a deposit to reduce the amount financed and the monthly payment. The right choice depends on your cash position and how you want the monthly figure to land.

The BUS grant comes off the price before any deposit calculation, which lowers the amount you'd need to finance in the first place. We talk through deposit options when you receive your quote.