Air Source Heat Pump Cost in Scotland 2026

Quick answer

An air source heat pump (ASHP) for a typical 4-bed Scottish home costs £12,000–£18,000 fully installed in 2026. With the Home Energy Scotland grant (£7,500) and loan (up to £7,500) stacked, out-of-pocket lands £0–£3,000 for most households.

What "fully installed" includes

A complete ASHP package isn't just the outdoor unit. Typical Ecoaim ASHP quote covers:

• 8–14kW Mitsubishi Ecodan or Daikin Altherma outdoor unit
• Indoor hydrobox + controls
• New 200–300L hot water cylinder (most existing cylinders are too small)
• Radiator sizing assessment + replacements where needed (older microbore radiators almost always need upgrading)
• Pipework upgrades, system balancing
• MCS heat-loss calculation + design
• DNO notification (heat pumps over a certain rating need G99)
• Commissioning + handover pack
• HES grant + loan application paperwork

The single biggest cost driver is radiator upgrade scope. Properties with newer (post-2010) modern radiators rated for low flow temperatures often need none; older properties with microbore systems can need 4–8 rads upgraded.

Out-of-pocket — the real number

For a typical Bathgate or Linlithgow 4-bed home with mid-range radiator work:

• Install cost: £15,500
• HES grant: £7,500
• HES interest-free loan: £7,500 (over 10 years, £62.50/month)
• Out-of-pocket cash: £500

For rural properties (Carnwath, Forth, parts of West Lothian):

• Install cost: £15,500
• HES grant (rural uplift): £9,000
• HES loan: £6,500
• Out-of-pocket cash: £0
• (Often the grant alone covers it plus a bit of contingency)

Running cost — heat pump vs gas vs oil

For a typical Scottish 4-bed at current 2026 prices:

ASHP wins on running cost for every fuel except subsidised mains gas in 2026 — and the gap widens as gas prices rise and electric tariffs adjust.

Pair ASHP with solar PV and you decarbonise heating at the same time as electrifying it.

SCOP — the number that matters

SCOP (Seasonal Coefficient of Performance) tells you the average ASHP efficiency across a Scottish heating season. Modern units deliver:

• 3.0–3.2 for older insulation-poor homes with high flow temperatures
• 3.4–3.8 for well-insulated homes with low flow temperatures
• 4.0+ for new-build homes with underfloor heating

We model your specific SCOP at quote time using the MCS heat-loss calculation. If the modelling shows SCOP < 2.8, we're transparent — ASHP may not save you money in your specific case until other insulation improvements are made.

When ASHP doesn't work (yet)

• Heat loss > 14kW — large old draughty stone houses. Address insulation first.
• Radiators all microbore + cement walls — radiator replacement cost can balloon
• Listed buildings with planning constraints — MCS 020 noise rules + heritage rules can clash
• Flat owners with shared roof/wall — outdoor unit placement is difficult

Choosing an ASHP installer

• MCS certified for ASHP (mandatory for HES grant + loan)
• MCS 020 fluent (noise emissions rules)
• Heat-loss calculation included as standard (not £200 extra)
• Radiator scope quoted explicitly (not "from £X")
• Workmanship warranty 5+ years (we offer 5 yrs; some offer 10)
• Manufacturer training (Mitsubishi MELCloud, Daikin Cloud Control — installer logins matter)

Typical timeline

• Day 0: Quote sent
• Day 7: HES grant + loan application submitted
• Day 35–49: HES approval
• Day 56: Materials ordered, install scheduled
• Day 70–77: Install (2–4 days on site)
• Day 84: MCS certificate issued, HES sign-off
• Day 90: Grant + loan funds released

Next step

Free heat-loss assessment + fixed quote in 24 hours. We handle HES grant + loan applications in-house. Call 03330 384 380 or use our online form.