How the estimate is built
The calculator starts from the same July 2026 budgeting bands used across this site: about £1,500 to £3,000 including VAT for a straightforward single-room UK split, and about £1,800 to £3,500 in many London situations. Extra rooms add a further allowance, with a slightly different profile for multi-split systems.
Checked extras add typical low and high allowances for pipe routes, access equipment, electrics, condensate pumps, premium kit, permissions and awkward parking. They are planning ranges, not a bill of quantities.
What this does not cover
- Server rooms or continuous IT process cooling. Use the server room cooling cost calculator.
- Multi-zone offices, shops or hospitality fit-outs. Use the commercial cost calculator.
- Major making-good, decoration or structural works
- Emergency call-outs or repairs to existing systems
- A guaranteed price from any installer
Use the result to prepare questions, then compare written scopes for the same rooms and positions.
Read the full UK and London installation cost guide, or use the quote comparison checklist.