TM44 Air Conditioning Inspections: A Legal Guide for Businesses

Yes, it is a genuine legal requirement. A TM44 inspection is the air conditioning energy assessment mandated by the Energy Performance of Buildings (England and Wales) Regulations 2012. The name comes from CIBSE Technical Memorandum 44, the document that sets out the assessment methodology assessors must follow.

The purpose is energy efficiency, not safety. The inspection checks that your cooling plant is sized correctly, working efficiently, and well maintained, then gives the building's responsible person practical advice on cutting energy waste and running costs. It is enforced in England and Wales by local authority Trading Standards (Scotland and Northern Ireland run separate but comparable schemes).

It is genuinely useful as well as compulsory: a poorly maintained system can quietly burn 20–30% more electricity than a well-tuned one, so the report often pays for itself.

The trigger is the effective rated output of your air conditioning, not the number of units or the size of the building. If the total rated cooling output across a building under one person's control exceeds 12kW, a TM44 inspection is required.

This catches more buildings than people expect. A single large ducted or VRF system can pass 12kW on its own, but so can several smaller split units added together. For example, five 3kW wall-mounted units serving one office add up to 15kW combined and fall squarely within the rules, even though no single unit is large. Purely domestic systems in a private home are exempt, but as soon as cooling serves a commercial or let space and tops 12kW, the duty applies.

Responsibility sits with the building owner, the tenant, or the managing agent, depending on who controls and operates the system. If that is you, the legal obligation to hold a valid report is yours.

At least once every five years. The first inspection should have taken place when the system was first put into service, or by the regulatory deadline if it was already installed when the rules came in. After that, a fresh assessment is due before the previous report's fifth anniversary.

The report itself does not legally expire, but you must always be able to produce a current one that is no more than five years old. A common and costly mistake is assuming the certificate "lasts forever" and then being caught without an in-date report during a sale, lease, or Trading Standards check.

An accredited assessor inspects the whole cooling installation, not just the boxes on the wall. A thorough TM44 assessment typically reviews:

The equipment and refrigeration plant — its size, age, condition, and efficiency, plus whether it is correctly matched to the cooling load of the space it serves (oversized systems are a frequent finding). Air handling and controls — thermostats, timers, zoning, and whether settings are sensible for actual occupancy. Maintenance records — evidence the system has been serviced and that refrigerant has been managed properly.

The assessor then produces a report listing the system's details, energy-saving recommendations, and any obvious faults or improvement opportunities, and lodges it on the central register. You receive a copy and an action list — none of the recommendations are mandatory to implement, but they are where the genuine cost savings live.

Failing to hold a current TM44 inspection report carries a fixed penalty of £300, and a separate £300 penalty applies for failing to keep a copy. Penalties can be issued per non-compliant building, and the underlying duty does not go away — you still have to commission the inspection after paying the fine.

Beyond the fine, the practical risks bite harder. Buyers, tenants, funders, and insurers increasingly ask for compliance documentation during transactions and due diligence, and a missing TM44 report can stall a sale or lease. It also signals a system that may be quietly wasting money, which is a poor look during any negotiation.

Only an accredited air conditioning energy assessor registered with a government-approved accreditation scheme may carry out a TM44 inspection and lodge the report. A general air conditioning engineer, however skilled, cannot legally issue one without that specific accreditation, so always check credentials before booking.

It pairs naturally with proper refrigerant maintenance. As an F-Gas/REFCOM registered Guildford installer, Tempest Air Conditioning keeps Surrey and South-East businesses on the right side of both the refrigerant handling rules and their five-yearly TM44 duty. If you are unsure whether your system crosses the 12kW threshold or when your last report was lodged, we can check it and arrange an accredited assessment.