Air conditioning maintenance contracts: what to check before you sign

A "four-hour response" in an air conditioning maintenance contract almost always means an engineer will arrive, or phone, within four hours. It does not mean your cooling will be working again in four hours, and the gap between those two promises is where most contract disputes start. Read every service level in a proposal and ask what event stops the clock: a call back, an engineer on site, or a fixed fault.

This page is about the agreement itself, the document a facilities manager or business owner signs. What a good service visit should measure is covered in our guide to commercial air conditioning maintenance, and the statutory intervals are set out in detail in TM44 inspection intervals and F-gas checks. Here the question is narrower: what should be written down, who carries which risk, and how you leave if it goes wrong.

The legal floor the schedule has to clear

A planned preventive maintenance (PPM) schedule can be generous, but it cannot be less frequent than the law requires. Two regimes set that floor, and both are measured on your plant, not on the contractor's standard package.

F-gas leak checks depend on how much refrigerant each system holds, expressed in tonnes of CO₂ equivalent (tCO₂e) rather than kilograms [1][2]:

Equipment that is hermetically sealed and labelled as such is exempt unless it holds 10 tCO₂e or more. Where a leak is found it must be repaired and re-checked within one month to confirm the repair worked [1]. The duty to have the checks done sits with the operator of the equipment, which is you, although responsibility for stopping leaks is shared with the technicians who work on it [1].

The second regime is the air conditioning energy inspection, usually called TM44. Systems with an effective rated output above 12 kW, counting all the units under one person's control together, must be inspected by an accredited energy assessor at intervals of no more than five years [3]. A missing report carries a fixed £300 penalty in England and Wales [3].

The government guidance says a maintenance contract may name the servicing company as the controller of the system, responsible for making sure inspections happen, but the landlord or occupier keeps a parallel duty to ensure the system has been inspected [3]. So if a contractor offers to "take on your compliance", that can be real and useful, provided it is written into the contract. It does not take the obligation off your desk. Ask for the TM44 due date and every system's tCO₂e figure to appear in the contract schedule itself, not in a sales letter.

Count visits against your plant, not the brochure

Most proposals offer one or two visits a year, and two, timed before the cooling season and before the heating season, is the usual baseline for offices and shops. That baseline moves with the asset. A server room unit running all year justifies quarterly attendance; a kitchen, gym or workshop fouls its filters far faster than a carpeted office; a lightly used meeting suite may need less. The F-gas table above is a floor underneath all of this, never a substitute for it.

The schedule should list every indoor and outdoor unit by location, model and serial number, with the refrigerant type and charge, and state the visit frequency against each one. A contract priced as "up to 12 units, twice a year" with no asset list leaves you unable to prove what was covered and leaves the contractor free to argue about anything added later. If a firm will not survey before quoting, the price is a guess and the scope will be argued over at the first breakdown.

Response, attendance and fix are three different promises

When you compare service levels, put each proposal's wording into the same three rows:

• Response: the time to acknowledge the call, often by phone.
• Attendance: the time until a qualified engineer is on site.
• Fix or make safe: the time until the system is working, or isolated and safe pending parts.

Then check the small print around them. Are the hours clock hours or working hours, and does a call at 4pm on Friday count from Monday morning? Is out-of-hours attendance included or charged as a call-out? Are priority levels tied to your assets (a comms room fault is priority one, a corridor cassette is not), or does the contractor decide on the day? Is there any consequence for missing the target, such as a service credit, or is the figure simply aspirational?

A short attendance time is only worth paying for on equipment where a failure stops trading, spoils stock or takes systems offline. Ask for tighter targets on those assets and accept slower ones elsewhere.

Parts, labour and the refrigerant line

Contracts split into roughly three shapes. Planned visits only, with every repair quoted separately. Visits plus labour on breakdowns, with parts and materials charged on top. And comprehensive cover, which includes parts, sometimes with a cap per claim and an age limit on covered equipment. Labour-only cover can look like most of the protection for a fraction of the price, until an older system needs a compressor or a control board.

Read the exclusions list for consumables, condensate pumps, access equipment and out-of-hours working, and for what happens when a unit fails beyond economic repair. On ageing plant, compare the cost of comprehensive cover with a phased replacement plan, because cover can become an expensive way of postponing a decision.

A system that needs topping up has a leak, so a contract that bills "regas" visits as a routine consumable is charging you repeatedly for the same fault. Write in that refrigerant is only added alongside leak detection and repair, that each addition is recorded with quantity and type, and that the contract states who pays for the gas itself. The F-gas phase-down limits how much HFC refrigerant can be placed on the market [2], so an open-ended "refrigerant at cost" clause is a real budget exposure on larger systems.

Records you should own when it ends

For any system at 5 tCO₂e or more, the operator must keep records of the gas charged at installation, gas added during maintenance and leak repairs, the dates and results of every mandatory leak check, how recovered gas was disposed of, and the name, address and certificate number of each company that installed or serviced the equipment. Those records must be kept for five years [4]. TM44 reports must be passed on to whoever takes over responsibility for the system [3].

Because those duties are yours, the contract should oblige the contractor to give you the records, in a format you can open without their portal, after every visit and in full when the contract ends. An asset register held only in a contractor's own software walks out of the door with them.

Length, renewal and the way out

Many contracts run for a year, some for three or more, often with automatic renewal. Before signing, find the notice period and the date by which you must give it, and whether a price increase on renewal needs your agreement. Look for a right to terminate for repeated missed service levels, not just for insolvency. If you are adopting a system someone else installed, expect a first survey visit that lists defects which predate the contract; agree in writing that those are quoted separately and that the contractor cannot later exclude a fault by calling it "pre-existing" without having recorded it at that survey.

For multi-let buildings, confirm the contract matches what the lease says about who maintains which plant. Our page for commercial landlords covers how that split usually falls.

What a contract costs, as far as we can say

We do not hold a rate card for maintenance, and contractors price it from a survey. As our own planning estimate, annual servicing for a commercial system starts from around £250 plus VAT and rises with unit count, with £600 to £1,500 a year a sensible budget for a mid-size installation and more where you want a response-time commitment. The breakdown sits in our commercial heat pump cost guide. A single small split costs far less to service; for domestic-scale per-visit figures see our air conditioning service cost guide.

Red flags in a proposal

• No site survey and no asset list, just a unit count and a price.
• Visit frequencies that fall below the F-gas interval for any system.
• A service level with no definition of when the clock stops.
• "Refrigerant top-ups included" with no mention of leak repair.
• Records available "on request" or only inside the contractor's portal.
• Automatic renewal with a long notice period and no performance exit.
• No company F-gas certificate number. A business that services equipment operated by others must hold company certification, renewed every three years, and its engineers must hold individual qualifications [5].

Common questions

Is a maintenance contract worth it for two or three split units? Often not as a comprehensive contract. A planned-visit agreement that covers the F-gas checks your systems need, keeps the warranty servicing documented and quotes repairs separately is usually enough. Put the money into faster cover only where a failure would cost you trade.

Can a contract make the maintenance company responsible for TM44? Yes, if it names them as the controller of the system, but you keep a parallel duty to make sure the inspection has happened [3]. Keep your own copy of every report.

Should maintenance terms be agreed at installation? It is the easiest point to do it, while commissioning data and warranty conditions are to hand and the installer knows every unit it has fitted. Ask for the maintenance proposal alongside the installation quote.

Next step

Airva does not carry out maintenance. If you are planning a new installation or a replacement and want the maintenance terms quoted alongside it, start a business enquiry and include your unit list and any response times you need. We'll review your requirements and match you with a suitable installer operating in your area, against the standard in how we check installers.