Most business owners know they need to service their air conditioning. Far fewer know that, if their systems add up to 12kW or more, they are also legally required to have those systems inspected by an accredited energy assessor — and to have the resulting report lodged on a government register. It is one of the most widely ignored obligations in UK building services, and it is the sort of thing that only surfaces at the worst possible moment: during a lease negotiation, a building sale, or an enforcement visit.
At AKS Air Conditioning, we have spent over 34 years working with commercial clients across Liverpool, the North West and nationwide. Here is a straight explanation of what a TM44 air conditioning inspection is, who needs one, and what to do with the report once you have it.
What Is a TM44 Air Conditioning Inspection?
TM44 refers to CIBSE Technical Memorandum 44, the methodology used to carry out air conditioning energy inspections in the UK. The legal requirement itself sits within the Energy Performance of Buildings Regulations.
The purpose is energy efficiency rather than safety. An accredited assessor reviews the air conditioning in a building and reports on how efficiently it runs, whether it is correctly sized, how well it is maintained and controlled, and what could be improved. The output is a written report with recommendations, lodged on the Energy Performance of Buildings Register.
Be clear about what it is not. It is not a service. It is not an F-Gas leak check. It repairs nothing. It is an independent assessment that sits alongside, not instead of, your maintenance regime.
Who Actually Needs One?
The trigger is the effective rated output of the air conditioning in the building.
- 12kW or above — an inspection is required.
- At least every five years — and the report must remain valid and available.
- Systems are aggregated — this is the point most people miss. If a building has several separate split systems under the control of one person, their combined output is what counts. Six 2.5kW units in a small office block will take you over the threshold, even though no individual unit comes close.
Responsibility normally sits with the person who controls the operation of the systems — in practice, the building owner, the managing agent, or the tenant, depending on how the lease is drafted. Assuming the other party has dealt with it is a common and expensive mistake. Check the lease.
Note also that Scotland operates a different regime under Section 63 of the Climate Change (Scotland) Act, so if you have sites north of the border the rules will not be identical.
The cost of ignoring it
The current fixed penalty for failing to have a valid inspection is relatively modest — £300 per building — with further penalties for failing to produce a report when asked. Government has consulted on raising these figures substantially, so treating the current level as an acceptable cost of non-compliance is a short-term view.
The bigger commercial risk is transactional. Missing compliance documentation slows down building sales, refinancing and lease renewals, and gives the other side something to negotiate with at exactly the point you have least leverage.
What the Report Typically Finds
In our experience, the same issues come up repeatedly across commercial buildings in the North West:
| Common finding | What it costs you |
|---|---|
| Systems significantly oversized for the space | Short cycling, higher running costs, premature component failure |
| Heating and cooling fighting each other | Two systems paying to cancel one another out, all year round |
| No time or zone controls | Empty offices cooled overnight and at weekends |
| Dirty coils and blocked filters | Reduced capacity, higher energy draw, poor air quality |
| Obsolete equipment on phased-down refrigerants | Rising gas costs and difficulty sourcing parts |
None of these are exotic. All of them show up on an electricity bill every single month.
Turning a Compliance Report into a Commercial Win
Here is where most businesses waste the exercise. The report gets filed, the box gets ticked, nothing changes. That is a missed opportunity: a TM44 report is effectively a free energy audit — a prioritised list of where you are burning money. The recommendations usually fall into three tiers.
1. Control and settings changes
Low or no cost. Correcting setpoints, establishing a proper dead band between heating and cooling, and setting time schedules that match actual occupancy. These often deliver the fastest payback of anything on the list.
2. Maintenance improvements
Moving from reactive callouts to a planned regime. Clean coils, correct refrigerant charge and functioning controls are what keep a system operating near its design efficiency. A structured commercial air conditioning maintenance contract also keeps your F-Gas leak checking and records in order, which is a separate legal duty.
3. Replacement and upgrade
Where equipment is at end of life, modern inverter-driven systems from Daikin and Mitsubishi — both of whom we partner with — can cut consumption dramatically against the fixed-speed kit they replace. If ventilation rates or air quality are flagged alongside the cooling, address ventilation at the same time rather than returning to the ceiling twice.
What We Suggest You Do This Month
- Add up the rated output of every air conditioning system in each building you control. If the total reaches 12kW, you are in scope.
- Find your last inspection report and check its date. If it is more than five years old, or you cannot find one, you have a gap.
- Check your lease to confirm who carries the obligation.
- If you need an inspection, book one with an accredited energy assessor — we can arrange this through our assessor partner.
- Once you have the report, act on the recommendations rather than filing them.
Compliance obligations across HVAC — energy inspections, F-Gas record keeping, ventilation standards — overlap more than most people realise. Our compliance page sets out how they fit together.
Talk to AKS Air Conditioning
If you suspect you are due an inspection, we can arrange one through our accredited assessor partner and then act on what the report finds. And if you already have a TM44 report sitting in a drawer, we can tell you what its recommendations are actually worth in reduced running costs — and what they would cost to implement.
With 34+ years of commercial HVAC experience and long-standing clients across retail, hospitality, leisure and offices, we are used to turning compliance paperwork into a sensible plan of work.
Call us on 01704 833 755 or get in touch for a straightforward conversation about your buildings.
