TM44 Air Conditioning Inspections Explained
TM44 air conditioning inspections are a legal requirement for larger AC systems. This guide explains what they cover, which systems need them, and how often.
In short
A TM44 inspection is a statutory energy assessment of air conditioning systems with an effective rated output over 12kW, required under the Energy Performance of Buildings Regulations. Carried out at least every five years by an accredited assessor, it reviews the system's efficiency and recommends improvements.
Which systems need a TM44 inspection
The requirement applies to air conditioning systems with an effective rated output of more than 12kW — assessed across the whole system, so multiple smaller units controlled together can together exceed the threshold and trigger the requirement. This captures a large proportion of commercial AC installations, from VRF systems and chillers to networks of split units. The inspection must be carried out by an accredited energy assessor and a report lodged.
What the inspection covers
A TM44 inspection (named after the CIBSE guidance it follows) assesses how efficiently the air conditioning is providing the building's cooling, and where energy and cost could be saved. It is an energy assessment rather than a maintenance service, but it draws on the system's condition and operation.
- The efficiency of the installed AC equipment relative to the cooling load
- Sizing — whether the system is appropriately matched to demand
- Controls and how the system is operated
- Maintenance condition as it affects efficiency
- Recommendations to improve efficiency and reduce running cost
The report and acting on it
The output is a TM44 inspection report, valid for five years, with recommendations for improving efficiency. Like an EPC, the value is in acting on the findings — improving controls, right-sizing equipment, and maintaining systems properly. Good documentation of the AC plant, its maintenance history, and energy data makes both the inspection and the follow-up improvements more effective, and helps demonstrate that recommendations have been considered.
Related maintenance checklists
Frequently asked questions
Keep AC plant documentation at hand
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