- Area
- Greater London
- Postcode district
- HA1
- Nation
- England
- Guide price
- From £10,650 inc VAT
- Survey
- Free for installation enquiries
Gas boiler to heat pump in Harrow: what to expect
A heat pump suits most Harrow homes, but the details decide how efficiently it runs. Our survey looks at insulation, radiators and hot water use room by room.
Rear gardens and side returns in Harrow usually offer a sensible spot for the outdoor unit, checked for airflow and neighbours. Installers in Harrow take out the old boiler and flue and seal the wall opening as part of the job.
Moving from mains gas to a heat pump means finding cylinder space, deciding what happens to the gas supply and comparing running costs on realistic assumptions.
- System or regular boiler homes with an existing airing cupboard
- Boilers that are old, unreliable or due for replacement
- Households ready to give up gas entirely and drop the standing charge
What's included
- Commissioning, MCS certificate and grant application in England and Wales where eligible
- System flush and radiator upgrades where the design calls for them
- Capping of the gas pipe at the boiler position where you are giving up gas
- Heat pump cylinder, outdoor unit and weather compensation controls
- Removal of the gas boiler, flue and any loft tanks
If your Harrow home still cooks on gas, we talk through whether to keep the supply or switch to an induction hob.
Grants and rules for heat pumps in England
Homes in Harrow can use the Boiler Upgrade Scheme, which takes £7,500 off the cost of an air source heat pump when it replaces fossil-fuel or electric heating. Replacing oil or LPG heating qualifies for £9,000 for installations from 21 July 2026 to 31 March 2027, and air-to-air systems for £2,500. The MCS-certified installer named in your quote applies for the grant and deducts it from the price.
There is no VAT on installing a heat pump anywhere in the UK until 31 March 2027. In England most houses can have an air source heat pump under permitted development, provided the unit meets the MCS noise and siting standards; the old 1 m boundary limit was removed on 29 May 2025. We flag listed buildings, flats and sensitive conservation-area positions at survey.
Guide prices for replacing a gas boiler with a heat pump in Harrow
Here are typical prices for replacing a gas boiler with a heat pump in Greater London, installed and including VAT. Use the guide price tool for a figure based on your home, then a survey confirms it in writing.
| Home | Typical size | Installed guide price | After £7,500 grant |
|---|---|---|---|
| 1–2 bedroom flat or small terrace | 4–5 kW | £10,650–£14,000 | £3,150–£6,500 |
| 2–3 bedroom terrace or semi | 5–7 kW | £11,750–£15,100 | £4,250–£7,600 |
| 3 bedroom semi or small detached | 6–9 kW | £13,450–£17,350 | £5,950–£9,850 |
| 4 bedroom detached | 8–12 kW | £15,700–£20,150 | £8,200–£12,650 |
| 5+ bedroom or larger older house | 11–16 kW | £18,500–£25,200 | £11,000–£17,700 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning.
How long is the heating season in Harrow?
Harrow sees roughly 7 hours 49 minutes of daylight in late December against 16 hours 39 minutes in June. Milder southern winters suit heat pumps well, though the system is still sized for a cold snap rather than an average day.
The steps for replacing a gas boiler with a heat pump in Harrow
- Start online with a guide price or call us.
- A home survey in Harrow gives us the room-by-room heat loss.
- Your written quote sets out the design, the price and the grant position where you live.
- Installation is booked for dates that suit you; most homes take 2–4 days on site.
- After commissioning you get a handover of the controls and settings, plus the certificates.
Replacing a gas boiler with a heat pump in Harrow: questions
How long does installation take in Harrow?
Most installations take 2–4 days on site. Jobs with several radiator changes or new pipework take longer, and your quote for a Harrow home states the expected time.
Do I need new radiators for a heat pump in Harrow?
Often some, not all. Heat pumps run best at lower water temperatures, so rooms with small radiators may need larger ones. The survey of your Harrow home gives a room-by-room list.
How long does a heat pump survey take in Harrow?
A home survey in Harrow usually takes one to two hours. The surveyor measures every heated room, checks windows, walls and radiators, and looks at where the outdoor unit and cylinder can go.
What if my gas boiler is fairly new?
A newer boiler can still be replaced, but the timing is worth weighing. Some owners switch when the boiler needs a major repair; others prefer to plan the change for a convenient time. Across the UK, heat pump installation is zero-rated for VAT until 31 March 2027. A hybrid system, which keeps the boiler alongside a heat pump, is another option, though it is not eligible for the Boiler Upgrade Scheme in England and Wales.
Do I need to replace the cylinder I already have?
Usually, yes. Older cylinders have a small internal coil designed for water from a boiler at around 60–70°C, and they cannot take in heat quickly enough at the lower temperatures a heat pump runs at. A heat pump cylinder has a larger coil. On its own, a cylinder supplied and fitted has a guide price of £1,200–£2,200, installed and including VAT, though it is normally part of the full system price.