A heat loss survey is a room-by-room assessment that calculates how much heat your home loses on a cold day, which tells you what size of heat pump you need and whether your radiators can deliver enough warmth. It follows the MCS method, the standard used for heat pump design across the UK, and it is the foundation for every other decision in your quote.
Homeowners in South Glamorgan thinking about insulation work can use the survey to see how it would change their heat pump size. A surveyor visits your home to measure each room, window and wall before any heat pump is sized. Design outdoor temperatures for South Glamorgan and the wider South Glamorgan come from local cold-weather data, not a national average.
Who it suits
- Landlords comparing properties before deciding where to switch first
- Homeowners planning insulation or building work who want to know the effect on heat demand
- Self-builders and architects who need emitter and system sizes early
- Homes with an existing heat pump that seems undersized or expensive to run
Grants and rules for heat pumps in Wales
In Wales the Boiler Upgrade Scheme gives £7,500 towards an air source heat pump (£9,000 if it replaces oil or LPG, from 21 July 2026 to 31 March 2027; £2,500 for air-to-air). The MCS-certified installer named in your quote applies to Ofgem for you, and the grant comes off your quote.
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.
Heat loss survey prices in South Glamorgan
These are guide prices for South Glamorgan, installed and including VAT. Your final price is fixed in a written quote after the survey and depends on the heat loss of the house, the radiators that need changing and where the unit goes.
| Survey | Guide price |
|---|---|
| Home survey and heat loss calculation with an installation quote | Free |
| Stand-alone heat loss survey and report | £150–£400 |
Inc VAT. A stand-alone report is for homeowners who want the design without an installation quote.
Towns we cover in South Glamorgan
We cover 6 towns in South Glamorgan for heat loss surveys. 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 loss surveys questions
Is the heat loss survey free?
Yes, for installation enquiries the home survey and heat loss calculation are free, and the results form the basis of your written quote. If you only want the calculation and report, for example for building plans or comparing quotes, a stand-alone heat loss survey has a guide price of £150–£400, including VAT. We confirm which applies when you book.
What is a design flow temperature?
The design flow temperature is the temperature of the water sent to your radiators or underfloor heating on the coldest design day. Heat pumps are more efficient at lower flow temperatures, typically around 35–50°C. Choosing it is a balance: a lower figure improves efficiency but can mean larger radiators in some rooms, so the design shows both.
Can I use the heat loss report to get other quotes?
Yes. A stand-alone heat loss report is yours to use, including sharing it with other installers so their quotes are based on the same figures. Comparing quotes like for like makes it easier to see differences in equipment, radiator upgrades and workmanship terms. The report states the assumptions used wherever construction could not be confirmed.
How long does a heat loss survey take?
A typical survey takes 1–3 hours on site, depending on the size and complexity of the home. Larger or older houses with mixed construction, extensions or many rooms take longer. The calculations and design are completed afterwards, and the results are included in your quote or stand-alone report.