- Area
- Mid Glamorgan
- Postcode district
- CF45
- Nation
- Wales
- Guide price
- From £9,500 inc VAT
- Survey
- Free for installation enquiries
What to know about replacing a gas boiler with a heat pump in Mountain Ash
Every property in Mountain Ash is different, so the design starts from measurements rather than a rule of thumb. That keeps the system the right size and the running costs predictable.
Rear gardens and side returns in Mountain Ash usually offer a sensible spot for the outdoor unit, checked for airflow and neighbours. Installers in Mountain Ash 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.
- Households ready to give up gas entirely and drop the standing charge
- Boilers that are old, unreliable or due for replacement
- Combi owners who can find space for a hot water cylinder
What's included
- Free survey with heat loss calculation and cylinder siting
- 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
- Commissioning, MCS certificate and grant application in England and Wales where eligible
- Heat pump cylinder, outdoor unit and weather compensation controls
If your Mountain Ash 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 Wales
Homes in Mountain Ash can use the Boiler Upgrade Scheme, which applies in Wales as well as England: £7,500 towards an air source heat pump, or £9,000 when it replaces oil or LPG heating for installations from 21 July 2026 to 31 March 2027. The MCS-certified installer named in your quote applies and deducts the grant.
Installing heat pumps is zero-rated for VAT across the UK until 31 March 2027. Wales has its own permitted development rules for air source heat pumps, so we check what applies to your property, including listed building and conservation-area constraints, at the survey.
What to budget for replacing a gas boiler with a heat pump in Mountain Ash
Guide prices for Mountain Ash and the rest of Mid Glamorgan are shown below, installed and inc VAT. We publish ranges rather than a single figure because design details move the price, and the written quote after survey fixes it.
| Home | Typical size | Installed guide price | After £7,500 grant |
|---|---|---|---|
| 1–2 bedroom flat or small terrace | 4–5 kW | £9,500–£12,500 | £2,000–£5,000 |
| 2–3 bedroom terrace or semi | 5–7 kW | £10,500–£13,500 | £3,000–£6,000 |
| 3 bedroom semi or small detached | 6–9 kW | £12,000–£15,500 | £4,500–£8,000 |
| 4 bedroom detached | 8–12 kW | £14,000–£18,000 | £6,500–£10,500 |
| 5+ bedroom or larger older house | 11–16 kW | £16,500–£22,500 | £9,000–£15,000 |
Installed, inc VAT: unit, cylinder, controls, minor pipework and commissioning.
Winter daylight and heating in Mountain Ash
Mountain Ash has about 7 hours 48 minutes of daylight at midwinter and 16 hours 40 minutes at midsummer. That swing matters if you pair a heat pump with solar panels: summer generation can cover much of the hot water, winter generation far less.
From survey to switch-on in Mountain Ash
- Send your postcode and a few details, or use the guide price tool.
- A surveyor visits your Mountain Ash home, measures every room and checks where the outdoor unit can go.
- You receive a heat loss design and a fixed written quote, with any grant shown where it applies.
- Installers fit the unit, cylinder and any radiator changes, typically over 2–4 days on site.
- The system is commissioned, set up with weather compensation and handed over with the paperwork.
Replacing a gas boiler with a heat pump in Mountain Ash: questions
Where would the outdoor unit go on a Mountain Ash house?
Usually at the side or rear, on a level base with space around it for airflow and servicing, away from bedroom windows where possible. The surveyor checks positions at your Mountain Ash home.
What size heat pump does a Mountain Ash home need?
It depends on the heat loss, not the postcode. As a rough guide, a 3 bedroom semi often needs 6–9 kW, but the room-by-room survey sets the actual size for your Mountain Ash home.
Do I need new radiators for a heat pump in Mountain Ash?
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 Mountain Ash home gives a room-by-room list.
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.