What Questions Should I Ask Before Accepting an AC Quote?

A good installer expects to be asked questions before you sign. If you have a quote in hand and something about it feels slightly off, that instinct is worth listening to. Below are the questions to ask before accepting an AC quote, covering what should be on the paper in front of you and what a confident, competent answer sounds like when you ask out loud.

The ten questions to ask before accepting a quote

1. Can you send me an itemised quote?

A single lump sum tells you nothing you can compare. Ask for the unit supply cost, labour, pipe run, electrical work and making good to be broken out separately. If an installer resists itemising, treat that as information in itself. There is rarely a good reason to keep the components of a domestic installation hidden from the person paying for it.

2. What is the model number of the unit you are quoting?

Without a model number you cannot check the unit’s efficiency rating, confirm it against the MCS product list if you are pursuing a grant, or price it independently against other quotes. “A leading brand” is not an answer. The exact model belongs on the paperwork before you sign anything.

3. What pipe run length are you allowing for, and what happens if it is longer?

Pipe run is one of the most common places a fixed-sounding price moves after the fact. A proper survey measures the actual run rather than assuming a standard distance. Ask what length is included in the quoted price and what the per-metre cost is if the real distance turns out to be greater.

4. Is electrical work included, and if not, why not?

Some installations need the consumer unit modified or a new dedicated circuit run. If this is excluded from your quote, ask directly whether it will definitely not be needed, and if there is any chance it will, get a cost for that scenario now rather than after the invoice arrives.

5. Does the price include making good?

Routing pipework through walls leaves holes and channels that need plastering and painting. Some installers fold this into the price, many do not. Confirm whether making good is included, and if it is not, whether you are expected to organise it yourself or the installer will quote for it separately.

6. Is the installer F-Gas registered?

Handling refrigerant without F-Gas certification is illegal in the UK, not just poor practice. Ask for the F-Gas registration number and check it against the Environment Agency’s public register. This takes a couple of minutes and rules out one category of installer you should never use.

7. Does this price reflect the current VAT treatment for qualifying installations?

Most fixed air conditioning systems are treated by HMRC as air source heat pumps and currently qualify for 0% VAT on installation, a relief that is in place until 31 March 2027. If your quote shows a different rate, ask the installer to explain why. A competent installer will either confirm the 0% treatment applies and correct the figure, or explain clearly why your specific installation does not qualify, for example because the unit is portable rather than fixed, or because it is a supply-only purchase with installation arranged separately.

8. What warranty comes with the unit and the installation?

These are two separate things. The manufacturer’s warranty covers the unit itself, typically around five years once registered. The installer’s workmanship warranty covers their labour, typically one to two years. Get both confirmed in writing, along with what happens if a fault appears within either period.

9. What does the noise assessment show for this specific location?

Since May 2026, outdoor unit noise for permitted development installations in England is assessed against a limit of 37 dB LAeq, calculated at the nearest neighbour’s habitable room window, not simply read off the unit’s datasheet at one metre. A proper quote should show the calculated figure for your actual proposed position, not just the manufacturer’s generic sound rating. Ask the installer to confirm the calculation has been done for your specific siting and that it passes.

10. What is your MCS certification number?

MCS certification is required if you want the installation to qualify for a BUS grant, and it signals a baseline level of technical competence even if you are not applying for one. Ask for the number and check it at mcscertified.com before you commit.

What the answers tell you

A good installer answers all ten without hesitation, and several will already be sitting on the quote in front of you. None of these questions should take more than a few minutes to answer properly. If an installer becomes vague, defensive, or tries to move you toward signing before you have finished asking, that reaction tells you more about the job ahead than the quote itself does.

If you have not yet worked out whether the headline price on your quote is reasonable in the first place, that is a separate question from the one this page answers. Our guide to air conditioning installation cost UK covers what fair pricing looks like, so you can use the two together, price first, due diligence second.

Final word

Ask all ten before you sign, not after. None of these questions are awkward to ask and none should slow down a competent installer. If the answers come easily, you can move ahead with confidence. If they do not, you have found that out before the money changed hands rather than after.

This site earns a commission if you go on to purchase or enquire through links on this page, at no extra cost to you. We remain editorially independent.