Heat pump replacement means removing an existing outdoor unit, and sometimes the cylinder and controls, and fitting a new heat pump sized and set up for the home as it is now. Air source heat pumps typically last 15–20 years, so systems fitted when the technology was newer to UK homes are reaching the point where repairs become harder to justify.
Across South Glamorgan and South Glamorgan, old units are removed with their refrigerant recovered by an F-gas certified engineer. New outdoor units in South Glamorgan may differ in size from the old one, so the base and position are checked at survey. Every replacement in South Glamorgan starts with a fresh heat loss survey, not just a copy of the old unit's size.
Who it suits
- Heat pumps nearing the end of their typical life with rising repair costs
- Units that have failed with a major fault, such as a compressor failure
- Older units where parts are becoming hard to source
- Oversized systems that short cycle and cost more to run than expected
Grants and rules for heat pumps in Wales
Homes in South Glamorgan 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.
Heat pump replacement prices in South Glamorgan
These are guide prices including VAT. The rate for your visit in South Glamorgan is confirmed before we book it, and any repair is priced in writing before parts are ordered.
| Work | Installed guide price |
|---|---|
| Replacing an old outdoor unit like-for-like | £6,000–£9,500 |
| Full system replacement, 2–3 bedroom terrace or semi | £10,500–£13,500 |
| Full system replacement, 3 bedroom semi or small detached | £12,000–£15,500 |
| Full system replacement, 4 bedroom detached | £14,000–£18,000 |
Installed, inc VAT. Grant funding rarely applies to replacing a heat pump, so these prices are shown without any deduction; we check eligibility at survey.
Towns we cover in South Glamorgan
We cover 6 towns in South Glamorgan for heat pump replacement. Each links to local guide prices and the grant position for Wales.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Cardiff | CF10 | Penarth | 7 h 50 min |
| Barry | CF62 | Dinas Powys | 7 h 51 min |
| Penarth | CF64 | Dinas Powys | 7 h 50 min |
| Cowbridge | CF71 | Llantwit Major | 7 h 50 min |
| Dinas Powys | CF64 | Penarth | 7 h 50 min |
| Llantwit Major | CF61 | Cowbridge | 7 h 50 min |
Heat pump replacement questions
Can I replace just the outdoor unit?
Often, yes, if the rest of the system is sound and correctly designed. The cylinder, controls and radiators can stay where they are compatible with the new unit. Some older cylinders and controllers do not work with a new heat pump, and the survey checks this. If the original design was the problem, replacing only the unit will not fix it.
How long does an air source heat pump last?
Air source heat pumps typically last 15–20 years, depending on the quality of the original design, how hard the unit has worked, where it is sited and how well it has been serviced. Units that short cycle or run at high flow temperatures for years may wear sooner. Annual servicing helps components last and spots problems early.
Will a new heat pump fit where the old one was?
Sometimes. A new unit may be a different size, weight or shape and may have different clearance requirements, so the existing base and position are checked at survey. The MCS noise assessment is carried out for the new unit, and a different position may be suggested if it improves performance or reduces sound at neighbouring windows.
What happens to my old heat pump?
The old outdoor unit is removed and disposed of responsibly. Its refrigerant is recovered first, which must be done by an F-gas certified engineer, and metals and components are recycled where facilities allow. If the old cylinder or controls are replaced too, they are removed at the same time, and pipework that is no longer needed is capped or taken out.