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.
Homes in the Highlands and Islands with a heat pump that never kept them warm can have the whole design checked before a new unit is chosen. Some of the earlier heat pumps in the Highlands and Islands are now reaching the age where replacement is worth considering. Every replacement in the Highlands and Islands 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
- Older units where parts are becoming hard to source
- Oversized systems that short cycle and cost more to run than expected
- Systems that were undersized and struggle in cold weather
Grants and rules for heat pumps in Scotland
The Boiler Upgrade Scheme does not apply in Scotland. Instead, homeowners in the Highlands and Islands can apply to Home Energy Scotland for a grant of up to £7,500 towards a heat pump, with up to £1,500 more for eligible rural and island homes, plus an optional interest-free loan of up to £7,500. You need a written funding offer before any work starts.
Heat pump replacement prices in the Highlands and Islands
These are guide prices including VAT. The rate for your visit in the Highlands and Islands 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 | £6,700–£10,650 |
| Full system replacement, 2–3 bedroom terrace or semi | £11,750–£15,100 |
| Full system replacement, 3 bedroom semi or small detached | £13,450–£17,350 |
| Full system replacement, 4 bedroom detached | £15,700–£20,150 |
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 the Highlands and Islands
We cover 12 towns in the Highlands and Islands for heat pump replacement. Each links to local guide prices and the grant position for Scotland.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Inverness | IV1 | Dingwall | 6 h 35 min |
| Fort William | PH33 | Oban | 6 h 45 min |
| Aviemore | PH22 | Inverness | 6 h 40 min |
| Dingwall | IV15 | Inverness | 6 h 34 min |
| Kirkwall | KW15 | – | 6 h 11 min |
| Lerwick | ZE1 | – | 5 h 49 min |
| Nairn | IV12 | Forres | 6 h 34 min |
| Portree | IV51 | – | 6 h 36 min |
| Stornoway | HS1 | – | 6 h 24 min |
| Thurso | KW14 | Wick | 6 h 17 min |
| Ullapool | IV26 | Dingwall | 6 h 29 min |
| Wick | KW1 | Thurso | 6 h 20 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.
Can I get a grant to replace my heat pump?
Usually not. In England and Wales, the Boiler Upgrade Scheme cannot normally fund a home that has already been funded for a heat pump, and it is aimed at replacing fossil-fuel or electric heating. Your circumstances may differ, so we check eligibility before quoting. In Scotland, check Home Energy Scotland's criteria. Northern Ireland has no dedicated grant at present.
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.