barnconversioncost.co.uk

Air-source heat pump for a barn conversion

Costs verified against BCIS Online (May 2026 release) and ONS Construction Output Price Index, April 2026. Class Q rules current to the 21 May 2025 GPDO amendment.

ASHP installed cost for a 200 m² barn lands at £11,000 to £18,000 after the £7,500 Boiler Upgrade Scheme grant. High-volume vaulted barns push capacity into 12-16 kW territory.

Sizing for a barn

A typical 200 m² well-insulated barn loses around 5-8 kW at design conditions; a poorly-insulated vaulted barn can hit 12-14 kW. ASHP capacity is matched to the heat-loss calculation produced by an MCS-certified installer; under-sizing leads to electric immersion top-up; over-sizing cycles the unit and shortens life.

BUS grant

The Boiler Upgrade Scheme pays £7,500 toward an air-source heat pump for English and Welsh properties. The dwelling must be your private property at the date of completion; the installer applies for the grant on your behalf. Barn conversions qualify once they have a postcode and EPC at completion.

Cost stack

ASHP unit (8-12 kW)
£3,500 - £5,500
Cylinder + buffer
£1,800 - £2,800
UFH first fix
£60 - £95 / m²
Installation labour
£3,500 - £6,500
Less BUS grant
-£7,500

Reviewed for build by O. Wakefield-Smith, Digital Signet research, Q2 2026. A chartered surveyor (RICS MRICS) sign-off is being procured for the live site. All numeric figures bracket their published BCIS, ONS or HMRC source on the page where they appear.