A TM44 inspection is a legal check of your air conditioning system to assess how efficiently it runs. You must have this assessment if the combined output of your system is more than 12kW. The inspection must be done by an accredited energy assessor.
During the visit, the assessor checks how your system is installed, controlled, maintained, and whether it’s suitable for your building’s cooling needs. The assessors don’t check if the unit works; they inspect how much energy it uses and whether that energy is being used efficiently.
After the inspection, you receive a report that includes:
-
A summary of how well your system performs
-
Any faults found and what can be done about them
-
Suggestions for improving settings, controls, or system size
-
Recommendations for reducing energy use and running costs
The goal is to help you improve energy efficiency and meet legal requirements. There is no obligation to follow the suggestions, but doing so can help you save money and reduce breakdowns in the long term.
Who must have a TM44 inspection and when?
You must arrange a TM44 inspection if the air conditioning system under your control has a total cooling output over 12kW. This includes systems made up of multiple smaller units if their combined output exceeds the threshold. The rule applies to both single buildings and multi-unit systems under one person’s control.
The timing depends on when your system was first put into service:
-
Systems installed on or after 1 January 2008 must be inspected within five years of installation.
-
Older systems over 250kW should have had their first inspection by 4 January 2009.
-
Older systems over 12kW should have had their first inspection by 4 January 2011.
After that, inspections must take place at least once every five years. For example, if your last inspection was in June 2020, your next one must be completed by June 2025. If no valid report exists by then, your system will no longer meet the legal requirement.
Only air conditioning systems that use refrigeration to provide comfort cooling fall under these rules. Dedicated process-cooling systems, such as those used in industrial or medical applications, are normally treated separately under other regulations.
Who is responsible for compliance?
The person responsible for the TM44 inspection is the one who controls how the air conditioning system operates. This doesn’t mean someone who only adjusts the temperature. It refers to whoever has technical and management control — such as a building owner, facilities manager, or sometimes a tenant, depending on the lease terms.
If you own the system or manage it under a service contract, it’s your duty to:
-
Make sure the inspection is carried out on time
-
Keep the latest inspection report
-
Pass the report to any new person taking over control of the system
If you take over responsibility and no report is provided, you must arrange a new inspection within three months.
In some cases, control may be shared. For example, if the landlord operates a central system but tenants have installed their own units, both parties may have separate responsibilities.
The duty to comply remains even if maintenance is outsourced. Contracting the work out doesn’t remove your legal obligation to ensure the inspection is completed and recorded.
What happens during the inspection?
A TM44 inspection involves a visual check of your air conditioning system, carried out on site by a qualified energy assessor. The purpose is to understand how the system operates, how it is maintained, and whether it runs efficiently under normal conditions. The inspection does not involve any hands-on repairs or changes to the system.
During the visit, the assessor looks at the condition of both indoor and outdoor units, checks for signs of poor maintenance such as blocked filters or damaged components, and assesses whether the system is suitable for the cooling needs of the space. Controls are also reviewed, including how the temperature is set, when the system runs, and where sensors are located. These factors can have a major effect on energy use and comfort.
Once the inspection is complete, the assessor produces a report. It outlines how efficient your system is, points out any issues that could affect performance, and offers advice on what could be improved. This might include adjusting control settings, making maintenance changes, or planning for future upgrades if the equipment is outdated or oversized.
What are the risks of non-compliance?
If you fail to carry out a required TM44 inspection, you may receive a penalty charge notice. The standard fine for not having a valid inspection report is £300. There is also a £200 fine if you do not provide the report to a Trading Standards Officer within seven days of being asked.
These penalties apply to whoever controls the air conditioning system. If you have taken over a building or system and did not receive a valid report, it is your responsibility to arrange an inspection within three months. Occupants who do not control the system are not held liable.
In practice, missing an inspection can also delay sales or leases. Legal advisors will often ask for the inspection report during the due diligence process. If it is not available, it could slow down or complicate the transaction.
To avoid problems, you should keep your report in a safe place and be ready to present it if requested. You are also expected to update it every five years to stay compliant.
Who can perform a TM44 assessment?
A TM44 inspection must be carried out by an accredited energy assessor. This person needs to be a member of a government-approved accreditation scheme and have up-to-date knowledge of how air conditioning systems operate.
The assessor is responsible for carrying out the inspection, preparing the report, and lodging it on the official register. Only reports completed by accredited assessors and entered into the register are legally valid. Once lodged, the report is given a unique reference number, which you can use to access it online.
At MGI, we are fully accredited to carry out TM44 inspections for systems of all sizes. Whether you operate a single unit or manage a large portfolio, we can help you meet the legal requirements and identify ways to improve efficiency. Our assessors are experienced, thorough, and trained to follow the correct procedures.
If you’re unsure whether your system qualifies or when your next inspection is due, we can advise you based on your current setup and building type. Just call our experts at 01865 251225 or leave your request via the contact form.
If you would like more information on the UK government regulations for air conditioning inspections in buildings, Department for local communities and government – Guide to air conditioning inspections for buildings