What an Air Conditioning Maintenance Contract Should Actually Specify

We took on an office estate a while back where the previous air conditioning contract had run for years without a single adverse report. Every visit signed off, every sheet filed, the facilities lead perfectly happy with the paperwork. On our first visit the engineer went to drop the filters out of a run of ceiling cassettes and found the grilles had been painted shut. Nobody had opened one in a very long time.

The contract said "filter clean". It said nothing about access equipment, and those cassettes sat above a stairwell that needed a tower. So an engineer had been wiping the visible face of the grille from a stepladder, ticking the line, and moving on. He was not being dishonest. He was doing exactly what he had been paid to do.

A maintenance contract worth paying for specifies four things in writing: the exact tasks on each planned visit and how often they happen, which statutory duties the contractor discharges on your behalf and which stay with you, what is included and excluded on parts, labour, refrigerant and access, and what response and attendance mean in hours rather than in adjectives. Miss any one of those and you are not comparing prices. You are comparing assumptions.

What you are actually buying

An air conditioning maintenance contract bundles three different products that most tender documents never separate. The first is planned servicing, the tasks an engineer performs on a schedule. The second is statutory compliance, the legal duties attached to owning and operating cooling plant. The third is reactive cover, what happens when something breaks between visits.

Cheap contracts price the first properly, imply the second without ever committing to it, and leave the third almost entirely open. That is not a scam, it is a commercial decision. The contractor cannot control how often unfamiliar equipment fails, so it prices only what it can control and charges for the rest as it arises. The problem is that the buyer usually reads the number at the bottom as if it covers all three.

Refrigeration buyers tend to understand this because a failed cold room has a food safety consequence and someone in the business owns that risk. Comfort cooling has no equivalent. Nobody gets sacked because the second floor is warm, so AC contracts get bought on price and rate card, and the scope goes unread until the summer it matters.

The visit scope, task by task

"Annual service" is not a specification. This is roughly what should be named line by line in the schedule, and what each line should say.

• Filters. Cleaned or replaced, and the contract must say which. If replaced, who supplies the media and to what grade. On a kitchen or a gym you will be replacing rather than washing, and that has a cost somebody has to own.
• Indoor and outdoor coils. Cleaned by a named method, not inspected. A fouled condenser is the most common reason a system that has never broken suddenly cannot hold setpoint in July.
• Condensate. Tray, trap, pipework and pump proved under load. Half the water damage claims I have seen on ceiling cassettes come from a drain that was visually clear and blocked the moment it ran.
• Fans and bearings. Noise, vibration and current draw, on the outdoor unit as well as the indoor.
• Electrical. Terminal tightness, contactor condition, running currents recorded against nameplate rather than described as satisfactory.
• Refrigerant. Operating pressures and superheat recorded, gas type and charge logged against the asset, not the site.
• Controls. Setpoints, schedules and any BMS interface checked. A surprising number of complaints about cooling turn out to be a timeclock somebody changed in March.
• Heating mode. If the system is reverse cycle, the heating side has to be proved. Where every planned visit is scheduled for spring, the heat pump function is effectively untested until it fails in November.
• Access. Who provides towers, podiums, roof permits and edge protection, and whether that time is chargeable. This single omission is why the cassettes in my opening story were never touched.

The frequency question should not be answered with a round number in a sales quote. It should come from the manufacturer's stated requirement for the equipment and from a recognised task schedule. SFG20, published by BESA Publications Ltd and described on its own site as "the industry standard for building maintenance", is the yardstick the FM industry uses. You do not have to buy a licence to benefit from it. You just have to ask a bidder which schedules they are working to, and watch what happens next.

The statutory duties a contract has to name

Air conditioning carries legal obligations that refrigeration does not, and they are the most commonly assumed and least commonly written part of any contract.

TM44 inspections

Government guidance is explicit that "all air conditioning systems with an effective rated output of more than 12kW must be regularly inspected by an energy assessor" and that "the inspections must be no more than five years apart". The same guidance confirms the threshold aggregates, covering "systems consisting of individual units which are less than 12kW, but whose combined effective rated output is more than 12kW". That catches a great many offices and retail units that assume they are below the line because no single cassette is large.

Two things follow for your contract. The duty sits with the person who controls the operation of the system, not with your maintenance contractor, and the inspection has to be carried out by an accredited energy assessor, who may not be the same person who services the kit. So the contract needs to state plainly whether inspections are in scope, out of scope, or arranged and subcontracted, and who lodges the report. Our guide to TM44 air conditioning inspections sets out how the cycle works in practice.

F-Gas leak checking and records

Leak checking is driven by refrigerant charge expressed as carbon dioxide equivalent, not by the physical size of the system. Government guidance on checking F gas equipment for leaks sets the lowest tier at 5 tonnes of CO₂ equivalent, checked at least once every 12 months, with the frequency increasing as charge increases, and states that "if you install a system to automatically detect leaks, you can double the period of time allowed between leak checks".

Record keeping is a separate duty and it lands on you. The guidance on recording F gas requires records "about the following equipment you operate or service if it contains F gas equivalent to 5 tonnes or more of carbon dioxide", and says "you must keep records for 5 years". A single split system will often sit below that threshold on charge alone. A VRF system serving three floors frequently does not. The practical ask is simple: require the contractor to log gas type and charge per asset at every visit, and to give you the records in a format you can export when they leave. Our overview of the F-Gas rules for businesses covers the thresholds in more detail.

Cooling towers and evaporative condensers

If any part of the estate uses a cooling tower or evaporative condenser, there is a notification duty that has nothing to do with your AC contractor and is regularly missed at handover. The Notification of Cooling Towers and Evaporative Condensers Regulations 1992 place the duty on "each person who has, to any extent, control of premises" to notify "the local authority in whose area the premises are situated". Water treatment is normally a separate specialist. Your contract should say so out loud rather than leaving a gap between two suppliers who each assume the other has it.

Parts, labour and the words that decide the invoice

Most disputes I see are not about workmanship. They are about a definition.

Consumables is the word to interrogate first. Ask for the list. Filters are the obvious one, but condensate pump cartridges, contactors, fuses, belts and remote handsets all sit in the grey zone, and different contractors draw the line in different places quite legitimately.

Refrigerant is usually excluded or capped, and where it is included there is often no obligation to find and fix the leak that caused the loss. Topping up a leaking system indefinitely is worse than useless. It is also getting harder to price honestly as the phase-down progresses, which is why a contract that promises to keep an ageing system running should be read alongside what the R410A phase-down means for availability.

PCBs and inverter drives are the expensive failures on modern systems, and they are commonly excluded by value threshold rather than by name. Ask what the threshold is.

Access and out-of-hours both carry uplifts. Both should be stated as a rate, in the contract, before you need them.

Response, attendance and the word "24/7"

I will keep this short because we have written about it at length elsewhere. Response, attendance and rectification are three different measurements that get quoted as if they were one. A four hour response can mean a phone call. Four hour attendance means somebody arrives. Rectification is almost never guaranteed, and honestly it should not be, because parts availability is outside anybody's control.

The instruction for a buyer is the same whoever you are contracting with: ask what the attendance window is, ask what happens outside trading hours, and get both in writing with the measurement named. Our piece on what 24/7 cover actually means takes the four common versions apart, and every one of them applies equally to air conditioning.

A thin contract versus one worth signing

Contract line	Thin version	Version worth signing
Planned visits	"Annual service"	Visits per asset per year, with the task list referenced to a named schedule
Filters	"Filter clean"	Clean or replace stated, media supplied by whom, and what happens when a filter is past cleaning
Access	Silent	Who provides towers, podiums and permits, and whether that time is chargeable
Coils	"Coil check"	Indoor and outdoor coils cleaned by a stated method, with readings before and after
Condensate	Visual inspection	Tray, trap, pipework and pump proved under load
Refrigerant	"Pressures checked"	Pressures and superheat recorded, gas type and charge logged per asset, leak check frequency stated against the charge
Heating mode	Silent	Reverse cycle proved once a year, in a month where a failure would be noticed
TM44	Assumed to be included	Explicitly in or out, with the lodging party named
Response	"24/7 emergency cover"	Separate figures for response and attendance, in hours, in and out of trading hours
Reporting	A signed job sheet	A per asset history you can export without asking permission

What changes across several sites

On one building the scope is the whole contract. Across twenty, the scope matters less than whether anybody can tell you what is actually installed.

The asset register is the contract. Every indoor and outdoor unit needs a unique identifier, a location, a model, a refrigerant type and charge, and a commissioning date. Without it you cannot see that four sites are consuming most of the reactive spend, you cannot answer an F-Gas question, and at re-tender you cannot give bidders a like for like basis to price against. You will get ten prices for ten different pieces of work and call it a competitive process.

Estates assembled by acquisition are almost always mixed manufacturer, which is fine mechanically and expensive administratively. It means multiple sets of fault codes, multiple parts channels and no single controls platform. A bidder who tells you this is straightforward has either not looked or is not telling you the truth.

Scheduling deserves as much attention as scope. Planned visits should land before the season that stresses the equipment, not in the quarter that suits the contractor's resourcing, and access windows for trading sites need to be agreed in the contract rather than negotiated site by site every year. If cooling matters to trade at a particular location, the same argument applies as for kitchen and front-of-house cooling, where a visit at the wrong hour is worse than no visit at all.

Finally, ask for reactive spend reported by asset rather than by site. Site totals tell you where money went. Asset level data tells you which three units are eating it, and that is the difference between renegotiating a rate and fixing the actual problem. Energy is worth watching for the same reason, and our running cost breakdown explains what a neglected system quietly does to consumption.

Questions to ask before you sign

• Which task schedule are the planned visits written against, and can I see it?
• Are filters cleaned or replaced, who supplies them, and is that in the price?
• What access equipment is included, and what happens on units you cannot reach from a stepladder?
• Is the TM44 inspection in scope, and if not, who arranges it?
• Who records F-Gas data, in what system, and can I export it if we part company?
• What exactly is a consumable under this contract, listed rather than described?
• Is refrigerant included, capped or excluded, and does the price include finding the leak?
• Does "response" mean a phone call or an engineer on site, and what is the figure for each?
• How is reactive spend reported, and is it broken down by asset?

Frequently asked questions

How often should commercial air conditioning be serviced under a contract?

The honest answer is that it depends on the equipment and the environment, and the contract should say where the frequency came from. Two sources should drive it: the manufacturer's stated servicing requirement for that model, and a recognised task schedule such as SFG20. A unit in a kitchen extract path or a dusty workshop will need attention more often than the same unit in a quiet office. Be wary of any bidder who gives you a frequency before they have seen the asset list.

Does an air conditioning maintenance contract include the TM44 inspection?

Frequently not, and that is the single most common assumption I see. TM44 inspections must be carried out by an accredited energy assessor and the report is lodged on the Energy Performance of Buildings Register, which is a different activity to servicing the equipment. Some contractors arrange it, some subcontract it, some leave it entirely with you. The contract should say which, in a sentence you can point at.

What is the difference between a service contract and a maintenance contract?

Commercially, very little, and the terms are used interchangeably in the UK market. What matters is what sits inside the document. A contract that only covers planned visits, with all breakdown work charged at a rate card, is a very different purchase to one that includes reactive labour, and both get sold under either name. Read the cover level, not the title on the front page.

Are filters included in an AC maintenance contract?

Sometimes cleaned, sometimes replaced, sometimes chargeable, and this is worth pinning down before you sign rather than after. Cleaning is included in most planned visit schedules. Supplying new media often is not, particularly on higher grade filtration or on sites where the filters cannot realistically be washed. Ask for the position in writing, per site, because it varies with the building.

Does the contractor hold my F-Gas records, or do I?

The record keeping duty sits with the operator of the equipment. Contractors usually hold the data in their own system as a practical matter, which is fine right up until the relationship ends and you discover you cannot get it out. Specify at tender that the records are yours, that they are maintained per asset, and that you can export them on request and on exit.

Can one contract cover both air conditioning and refrigeration?

Yes, and on a mixed estate it usually should, because a single asset register and one escalation route is simpler to run than two. What it should not do is use one scope of works for both. The task schedules, the statutory duties and the consequences of failure are different, so a combined contract needs separate annexes rather than a shared paragraph that covers neither properly. The same applies to servicing and repairs generally, where the reactive terms deserve their own section.

Before you re-tender

Most estates I look at do not need a more expensive contract. They need a more specific one. The money is rarely lost on the rate, it is lost in the space between what the buyer assumed a visit included and what the document actually obliged anybody to do, and that space only shows up in a hot week or an audit.

Reviewing air conditioning cover across a portfolio is worth doing with the asset list open and the old contract next to it. Talk to us about planned air conditioning servicing and we will go through the scope with you honestly, including the parts a contractor would rather you did not ask about.

If the same conversation applies to refrigeration across your estate, the questions are near identical, and we set them out in commercial refrigeration maintenance.

About the author: Ali Elm runs Be Cool Refrigeration & Air Conditioning, a family-run London firm that has been installing, servicing and repairing commercial refrigeration and air conditioning since 2004. His F-Gas certified team has delivered more than 2,000 projects across London and the South East.

Last updated: 8 September 2026