TM44 Air Conditioning Inspections Explained: Who Needs One and When

TM44 is the one commercial compliance duty that most building owners have never heard of, and yet it is as mandatory as an EPC. If the air conditioning in your building adds up to more than 12kW, an accredited assessor must inspect it at least every five years and lodge a report. Beyond the box-tick, that report is usually the clearest account anyone has given you of why your energy bill is what it is.

What TM44 is

“TM44” is the name of the CIBSE technical memorandum that sets out how air-conditioning inspections are done, and it has become shorthand for the inspection itself. The legal requirement sits in the Energy Performance of Buildings (England and Wales) Regulations 2012, which implement the requirement for regular inspection of air-conditioning systems. GOV.UK’s guidance summarises who it applies to.

General information, not legal advice.

Who needs one

Anyone who controls the operation of an air-conditioning system with an effective rated output of more than 12kW. That is the combined output of all the units in the building under common control, not the largest single unit, which is why several small splits can tip a building over the line. Our guide to the 12kW threshold works through the arithmetic. The duty falls on whoever controls the system: usually the occupier for their own units, or the landlord for a central system.

How often

At least every five years. A new system must have its first inspection within five years of being brought into service. The lodged report shows its date, so the next due date is simple to diarise, and you can check whether a report exists for your building on Find an energy certificate.

Who can carry it out

Only an accredited air-conditioning energy assessor, registered with a government-approved accreditation scheme. Assessors are accredited at levels matching system complexity: simpler packaged systems at one level, complex centralised systems at a higher one. The assessor lodges the report on the register once complete.

What the inspection covers

The assessor examines the refrigeration equipment, air-handling and distribution, controls and metering, and the building’s cooling demand. The report comments on the efficiency of the systems, whether they are correctly sized for the load, how well they are controlled and maintained, and recommends improvements, often including control changes and maintenance that cut running costs quickly. It is advisory on the improvements and mandatory on the inspection.

Penalties and transactions

Failing to have a valid inspection report, or failing to provide it to a buyer or new tenant on request, can attract a fixed penalty. Enforcement is by trading standards. The more practical consequence is in transactions: buyers and tenants ask for the report, and a missing one is a due-diligence flag.

Why it matters beyond compliance

Air conditioning is often the largest single energy load in a commercial building, which means it is also one of the biggest levers on the building’s EPC rating. The TM44 report’s recommendations are a ready-made list of the control and maintenance changes most likely to lift that rating. Our guide to air conditioning and EPC ratings connects the two.

Sources & further reading

• Energy Performance of Buildings (England and Wales) Regulations 2012 — the regulations requiring air-conditioning inspections
• Air conditioning inspections for buildings (GOV.UK) — the government guidance on who needs one and when
• Find an energy certificate (GOV.UK) — where lodged inspection reports can be found

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