A high-temperature heat pump is an air-to-water heat pump able to produce flow temperatures of around 65–75°C, close to what a gas or oil boiler delivers, instead of the 35–50°C at which standard heat pumps run most efficiently. That means existing radiators can often heat rooms much as they do now, without being replaced with larger ones.
Period houses in South Glamorgan with original cast-iron radiators may suit a high-temperature unit that works with them. In South Glamorgan, rooms with large bay windows are often the ones where radiator output is checked most carefully. Installers in South Glamorgan set the weather compensation curve so the unit runs cooler on mild days.
Who it suits
- Owners who want fewer changes inside the house
- Rooms with no wall space for a larger radiator
- Homes with microbore pipework that would be disruptive to replace
- Period and listed homes where the radiators are part of the character
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.
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.
High-temperature heat pumps prices in South Glamorgan
The ranges below are typical installed prices for homes in South Glamorgan, including VAT. A survey sets the exact figure, because two similar-looking houses in South Glamorgan can need quite different radiators and pipework.
| 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. A high-temperature unit typically adds £1,500–£3,000.
Towns we cover in South Glamorgan
We cover 6 towns in South Glamorgan for high-temperature heat pumps. 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 |
High-temperature heat pumps questions
Do I still need a hot water cylinder?
Yes. Like other air-to-water heat pumps, a high-temperature unit heats a stored cylinder rather than supplying hot water on demand. Its higher output temperature can help the cylinder reach the temperature needed for its periodic legionella cycle with less reliance on the immersion heater. The cylinder is sized for your household at survey.
Is a high-temperature heat pump right for a listed building?
It can be, because it reduces the need to replace period radiators or lift historic floors for new pipework. The outdoor unit position still matters: in England, listed buildings need listed building consent for external works, and the other nations have their own rules. We check what applies at survey and look for discreet positions, such as a rear courtyard or behind an outbuilding.
Can a heat pump work with my existing radiators?
Often, yes, especially with a high-temperature unit. Standard heat pumps run most efficiently at 35–50°C, so some radiators may be too small at those temperatures. A high-temperature unit can run at around 65–75°C, so existing radiators can usually heat rooms much as they do with a boiler, at a cost in efficiency. The survey checks every radiator against its room's heat loss.
Why do many high-temperature units use R290?
R290 is propane, a natural refrigerant with a very low global warming impact. Its properties make higher water temperatures more achievable than with some earlier refrigerants. Because it is flammable, manufacturers set clearance zones around the outdoor unit from windows, doors, drains and other openings, which the survey uses when choosing a position.