Compare quotes by the lines under the headline, not by the headline. The decision is whether the price includes the core drill, the trunking, the condensate route, the electrics, access and making good, or whether those appear later as extras. Model codes should be on the page. A survey is what makes those lines real. Refrigerant charging and the F-gas record sit with a certified company, and they should be named on the quote rather than assumed.
A wall unit and the word installation
A wall unit, an outdoor unit and 'installation' is not a scope. Ask where the hole is, how long the pipe run is, whether trunking is inside or outside, and who makes the plaster and the brick good. A short run in plastic capping may be inside a normal install. A long run across several rooms, or a chase and replaster, is a different line and should be priced.
The electrical line under the headline
Electrics are often the quiet extra. A spare way and a short circuit are not the same job as a board change. The quote should say which one it includes. Isolation within reach of the engineer belongs there too, along with access equipment and warranty registration.
- Indoor and outdoor model codes.
- Pipe length, trunking and the wall finish.
- Gravity drain or a condensate pump.
A lump sum that left out the pump
Two quotes can differ by a thousand pounds because one of them left out the pump and the new circuit. As a 2026 illustration, those omitted lines are often hundreds of pounds each on an ordinary house, and more when the drain is far away or the board is obsolete. That is an illustration, not a tariff. Your survey is the price.
Subject to survey after the survey
Watch for 'subject to survey' on a quote that was already supposed to be after a survey. Either the visit has happened and the lines are fixed, or you are still looking at a guess. Do not pay a large deposit against a guess.
Commissioning and the F-gas record
The finished system needs commissioning, a record of the refrigerant work and warranty registration with the manufacturer. If those are missing from the quote, the cheap figure may stop the day the unit is hung. F-gas certification is what allows the company to do the refrigerant circuit. Ask for it before you accept. At the end you should hold commissioning details, the F-gas record from the certified company, warranty registration and the model codes that match the machines on the wall.
Planning Portal conditions on the outdoor unit
In England, an outdoor unit still has to satisfy Planning Portal conditions, or have consent where those conditions do not apply. A quote that ignores a flat, a listed building or a conservation area has a missing line, even if the equipment price looks sharp. If one firm includes a pump and another hopes for gravity, you want that difference visible before you choose.
Frequently asked questions
Should I pick the lowest lump sum?
Only after the missing lines are written back in. The lowest headline often excludes the pump, the electrics or making good, and those return on install day.
Core buying guides
Start with these high-intent guides, then dig into the rest of the library.
Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.