Air conditioning for extensions and kitchen-diners across Cornwall
In Truro, a side wall of a single-storey extension is usually the neatest place for the indoor unit. An extension in Truro with a roof lantern or large glazed doors can overheat quickly on a sunny afternoon. Coastal breezes help, but inland South West towns and glazed rooms still see uncomfortable peaks.
Prices in Cornwall
Budget around £1,450–£4,450 per space including VAT for air conditioning for extensions and kitchen-diners in and around Cornwall. It sits near the middle of UK prices. Concealed pipework, access equipment for high walls and any electrical work are what push prices towards the upper figure. For reference, the Large single option in Cornwall (one 5–7 kW unit for a large glazed space) usually comes to about £2,050–£2,850.
Single unit
One 3.5–5 kW unit for a medium extension.
Large single
One 5–7 kW unit for a large glazed space.
Twin units
Two indoor units on a multi-split for long or L-shaped spaces.
Guide prices show VAT at 20%. HMRC treats most fixed air conditioners and air-to-air heat pumps installed in homes as energy-saving materials, zero-rated until 31 March 2027 when we supply and fit them. If your installation qualifies, your quote shows 0% VAT and a lower price. Servicing, repairs, cleaning and controls are charged at 20%.
Planning and permissions
Since 29 May 2025, England's permitted development rules allow larger outdoor units (up to 1.5 m³) and no longer require a 1 m gap to the boundary, provided the MCS 020(a) noise check is met. Listed buildings and pitched-roof installs still need permission.
The survey
Surveys in Cornwall cover heat gain, pipe routes, electrics, access and noise to the nearest neighbour, so surprises on the day are rare. The free survey is where the real price is set: room measurements, pipe and drain routes, electrical checks and the outdoor unit position, all written into your quote.
What is included
Included with air conditioning for extensions and kitchen-diners across Cornwall:
- Free survey with glazing and roof heat-gain check
- Handover of the remote or app
- Placement clear of the hob and oven
- Hidden routes during the build, or neat surface routes after
- One or two units sized for the whole space
- Pressure test, vacuum and commissioning
Towns in Cornwall
Pick your town for local details, or see every service in Cornwall.