In Gravesham, Sevenoaks, Dartford the average household spends £934 a year on heating — 3% lower than the UK average of £960. Typical homes are 99.5 m² with 5.0 rooms. The local population is around 17,119 residents (Census 2021). Switching to an air-source heat pump could save up to £374 a year for an average home after the £7,500 Boiler Upgrade Scheme grant.


Areas covered

Longfield, Hartley, New Ash Green, New Barn, Fawkham

See more in the DA area hub.

Typical air-source heat-pump installation costs range from about £6,000 at the low end to roughly £18,000 at the high end. Most homes fall somewhere between £7,000 and £15,000. These prices are before the £7,500 BUS grant (in addition, qualifying rural and island homes in Scotland may receive a further £1,500 uplift under the Home Energy Scotland scheme, for up to £9 000 of grant funding).

Installation costs in Gravesham, Sevenoaks, Dartford are around 15% higher than the UK average.

CategoryNational cost range Adjusted for DA3 (×1.15) Net after £7,500 BUS grant
Small flats / simple installs £ 6,000 – £ 7,000 £ 6,900 – £ 8,050 from ~£ 1,000*
2–3-bed semis / moderate upgrades £ 8,000 – £ 12,000 £ 9,200 – £ 13,800 £ 1,700 – £ 6,300
Large detached / extensive work £ 13,000 – £ 18,000 £ 14,950 – £ 20,700 £ 7,450 – £ 13,200

* Minimum net costs rarely fall below £1,000 after grant, since most installs incur at least minor extra work.

Lower end
  • Minimal groundwork or plumbing modification required
  • Well-insulated homes that only need a compact ASHP unit
Mid end
  • Moderate radiator or underfloor-heating upgrades
  • Typical pump size (8–12 kW)
Upper end
  • Large detached houses or older properties needing major pipework
  • Extensive insulation or radiator replacement
  • Multi-zone controls and bespoke system design

Heat pump FAQs

How much does a heat pump cost here?

About £4,767 for a typical 3-bedroom home after the £7,500 grant.

How much can I save on heating bills?

Roughly £374 per year for the average home at current price-cap rates.

  • £934 Average Heating Cost UK avg £960
  • 99.5 m² Median Floor Area UK avg 84.7 m²
  • 5.0 Average Rooms UK avg 4.4

Local energy snapshot

Latest tariff window: 2025Q4

Ofgem region & price cap

South East · 26.92p/kWh · 47.60p/day

PV potential (south-facing)

1,025 kWh per kWp/year

Dwelling mix

House 66.2% Flat 12.1% Bungalow 19.3% Detached 36.8% Semi-detached 21.7% Terraced 40.3%

EPC certificates

3,509 on record

Ready to get started?

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Also in Your Area: Solar Panel Potential

Heat pumps increase electricity usage. Solar panels can offset your higher bills.

Without heat pump:

Solar saves ~£1,031/year
Payback: 11.8 years

With heat pump:

Solar saves ~£1,239/year
Payback: 9.8 years

  • Typical system 6 kW
  • Installation cost ~£12,200
  • Annual generation 6,149 kWh

See detailed solar data for DA3 →

Data from our sister site, Solar By Postcode UK

Compare nearby areas: DA1 (Bexley, Dartford) · DA2 (Sevenoaks, Dartford) · DA4 (Sevenoaks, Dartford) · DA5 (Bexley, Dartford) · DA6 (Bexley)

Heat Pump Installation & Ownership Guide

Timeline, planning rules, maintenance and what to expect
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Official Heat Pump Resources & Data Sources

BUS, Ofgem, planning rules, MCS and the data behind the numbers
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