Replacing an old outdoor unit like-for-like has a guide price of £6,000–£9,500, installed and including VAT. Where the system needs re-sizing or other upgrades, the written quote sets out each item. Grant funding rarely applies to replacements, because the Boiler Upgrade Scheme in England and Wales cannot usually fund a home already funded for a heat pump, so we check eligibility before quoting.
Some of the earlier heat pumps in Dorset are now reaching the age where replacement is worth considering. Every replacement in Dorset starts with a fresh heat loss survey, not just a copy of the old unit's size. New outdoor units in Dorset may differ in size from the old one, so the base and position are checked at survey.
Who it suits
- Older units where parts are becoming hard to source
- Units that have failed with a major fault, such as a compressor failure
- Heat pumps nearing the end of their typical life with rising repair costs
- Oversized systems that short cycle and cost more to run than expected
Grants and rules for heat pumps in England
In England 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), and since 28 April 2026 a valid EPC is no longer needed. The grant is applied for by the MCS-certified installer and shown as a deduction on your quote.
Heat pump replacement prices in Dorset
These are guide prices including VAT. The rate for your visit in Dorset 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 | £6,050–£9,600 |
| Full system replacement, 2–3 bedroom terrace or semi | £10,600–£13,650 |
| Full system replacement, 3 bedroom semi or small detached | £12,100–£15,650 |
| Full system replacement, 4 bedroom detached | £14,150–£18,200 |
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 Dorset
We cover 12 towns in Dorset for heat pump replacement. Each links to local guide prices and the grant position for England.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Bournemouth | BH2 | Christchurch | 7 h 57 min |
| Poole | BH15 | Bournemouth | 7 h 57 min |
| Weymouth | DT4 | Dorchester | 7 h 58 min |
| Christchurch | BH6 | Bournemouth | 7 h 57 min |
| Ferndown | BH22 | Wimborne Minster | 7 h 56 min |
| Dorchester | DT1 | Weymouth | 7 h 57 min |
| Wimborne Minster | BH18 | Ferndown | 7 h 57 min |
| Blandford Forum | DT11 | Wimborne Minster | 7 h 56 min |
| Bridport | DT6 | Dorchester | 7 h 57 min |
| Sherborne | DT9 | Yeovil | 7 h 55 min |
| Swanage | BH19 | Poole | 7 h 58 min |
| Wareham | BH20 | Poole | 7 h 58 min |
Heat pump replacement questions
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.
How much does it cost to replace a heat pump?
Replacing an old outdoor unit like-for-like has a guide price of £6,000–£9,500, installed and including VAT. Re-sizing, a new cylinder, radiator upgrades or new controls add to that, and each is itemised in your written quote. The final price is fixed after a survey, once we know what the existing system needs.
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.
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.