Heat pump FAQs

An air source heat pump costs £8,000 to £14,000 installed before grant on most houses. After the £7,500 Boiler Upgrade Scheme grant, most households pay a net £1,500 to £6,500. Ground source runs £20,000 to £35,000 before the same grant, and air to air is £2,000 to £3,500 for a single room.

The same as the national range, with one local wrinkle: a lot of the housing stock here is Victorian and solid walled, which pushes heat loss and therefore unit size up. Expect the middle to upper end of the range for a period property, and the lower end for anything built after about 1990.

Three to five working days on site for most domestic air source installations, two for a straightforward swap, a week or more for large period properties. Ground source adds several days to several weeks for groundworks. From survey to commissioning, allow four to eight weeks including the grant process.

Day one covers the outdoor unit base, siting and pipework route. Days two and three cover the cylinder, internal pipework and radiator changes. The last day is electrical connection, filling, commissioning and handover. We agree the window without heating and hot water with you in advance.

More than a boiler swap, considerably less than a kitchen. Expect floorboards up along pipework routes, dust from core drilling, and one to two days without heating and hot water during the changeover.

Around £11,000 before grant for a typical three or four bedroom house on air source, so roughly £3,500 net after the £7,500 grant. The average hides a lot: radiator upsizing alone can swing a quote by £3,500.

Yes. They produce heat well below freezing, though output and efficiency fall as it gets colder. That is why the system is sized against a design temperature for the area rather than an average, so it still meets the load on the coldest days.

Usually some, not all. Heat pumps run at a lower flow temperature than boilers, so radiators must be larger to emit the same heat. In a typical three-bed we replace four to six. The heat loss survey identifies exactly which rooms need it.

Most domestic air source installations in England are permitted development. The rules were relaxed in May 2025: the one metre boundary rule went, the size cap rose to 1.5 cubic metres, and detached homes can have two units. The MCS 020(a) noise assessment still applies. Listed buildings always need consent, and conservation areas and Article 4 zones need checking, which matters in central Tunbridge Wells.

Around 40 to 50dB at one metre, roughly a fridge in the next room. For permitted development the calculation must come in at or below 37dB(A) at the nearest noise-sensitive window. We run that assessment at survey and it determines where the unit can be sited.

It depends on the flow temperature achieved. A system running at 35 to 45°C with a seasonal efficiency around 3.5 is usually comparable to or slightly cheaper than mains gas, and clearly cheaper than oil, LPG or electric heating. A badly designed system running at 55°C or higher can cost more than the boiler it replaced.

It comes from a room-by-room heat loss calculation, not floor area. Most three or four bedroom houses land between 6kW and 12kW, but a solid wall Victorian property can need substantially more than an insulated modern house of the same size. Oversizing is as damaging as undersizing, because it makes the unit cycle inefficiently.

Not if you want the grant. The Boiler Upgrade Scheme requires the fossil fuel system to be fully removed or permanently decommissioned, and hybrids are excluded. A correctly sized heat pump should not need a backup.

Air source takes heat from the outside air using an outdoor unit. Ground source takes it from buried loops or boreholes, with the heat pump itself indoors. Ground source is more efficient and cheaper to run, but costs two to three times more to install for the same grant, and it needs land or drilling access.

One that blows warm air directly into the room rather than heating water for radiators. It also cools in summer. It does not produce hot water. It is the cheapest heat pump type and now attracts a £2,500 grant, provided your old gas boiler is fully removed.

The Boiler Upgrade Scheme pays £7,500 for an air source or ground source heat pump, £2,500 for air to air and £5,000 for biomass in eligible rural properties. Off-gas-grid homes replacing heating oil can get £9,000 for installations between 21 July 2026 and 31 March 2027.

No. Your MCS-certified installer applies to Ofgem on your behalf and the grant is deducted from your invoice, so you only ever pay the net figure. We handle the paperwork.

No. The EPC requirement, and the condition about outstanding loft and cavity insulation recommendations, were removed. That brought a lot of older Kent and Sussex property back into scope.

Yes, annually. It keeps efficiency up, catches refrigerant issues early and is a condition of most manufacturer warranties. It is a smaller job than a boiler service but it should not be skipped.

Typically 15 to 20 years for the heat pump itself, against 10 to 15 for a gas boiler. Ground loops and boreholes last far longer, commonly quoted at 50 years or more, so a ground source replacement later on only means changing the indoor unit.

Tunbridge Wells and roughly a 20-mile radius, covering west Kent and the High Weald of East Sussex. That includes Tonbridge, Sevenoaks, Crowborough, Wadhurst, Cranbrook, Uckfield, East Grinstead, Paddock Wood, Heathfield and Maidstone.