Air conditioning for extensions and kitchen-diners in St Austell
An extension in St Austell 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.
For a kitchen-diner in St Austell, we place the indoor unit clear of the hob and plan the outdoor unit at the rear. We cover St Austell as part of Cornwall, roughly 13 miles from Truro. Homes in PL25 are all within our coverage.
Prices in St Austell
Budget around £1,450–£4,450 per space including VAT for air conditioning for extensions and kitchen-diners in and around St Austell. That is broadly in line with national guide prices. Concealed pipework, access equipment for high walls and any electrical work are what push prices towards the upper figure. On our South West England figures, the Large single option (one 5–7 kW unit for a large glazed space) is 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
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. A survey in St Austell usually takes one to two hours. We measure the rooms, check the walls and the consumer unit, agree the outdoor unit position with you and photograph the pipe routes.
What is included
Every job in St Austell includes:
- Placement clear of the hob and oven
- Pressure test, vacuum and commissioning
- Hidden routes during the build, or neat surface routes after
- Handover of the remote or app
- Free survey with glazing and roof heat-gain check
Nearby
Nearby, we also cover Bodmin (9 miles), Truro (13 miles) and Liskeard (16 miles). See all services in St Austell or air conditioning for extensions and kitchen-diners across Cornwall.