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What Is a TM44 Inspection (and Why You Need One)

A TM44 inspection, also known as an Air Conditioning Energy Assessment (ACEA), is a legally required evaluation of commercial air conditioning systems in the UK. If your system’s output exceeds 12 kW (or multiple units combined do), you must arrange a TM44 inspection every five years.

While compliance is non-negotiable, a good TM44 can also reveal energy savings, improve performance, and reduce carbon emissions — making it more than just a regulatory burden.

Modern office interior with comfort cooling air conditioning, employees working comfortably at desks, visible ceiling AC vents

What Does “TM44” Mean & Where It Comes From

The term “TM44” originates from a Technical Memorandum (TM44) published by CIBSE (the Chartered Institution of Building Services Engineers), which sets out guidelines and best practice for air conditioning inspections.

These inspections were introduced under the Energy Performance of Buildings (Certificates & Inspections) Regulations, which implement the European Energy Performance of Buildings Directive (EPBD) in UK law.

Who Needs a TM44 Inspection?

You need a TM44 inspection if:

  • Your air conditioning system has an effective rated output above 12 kW (cooling).

  • Multiple smaller units controlled by the same person add up to more than 12 kW.

  • You manage or control the HVAC systems (as building owner, facilities manager, or landlord). 

If your system is below 12 kW or all units combined are below that threshold, a TM44 inspection is not required under the regulation.

What Happens During a TM44 Inspection?

A TM44 inspection involves the following steps:

  1. Data gathering & site review — The assessor collects system details: age, capacity, configuration, control type, previous maintenance records.

  2. Visual inspection — All major components are inspected: outdoor units, indoor units, ducting, controls, filters, refrigerant circuits. Faults, leakage, wear and inefficiencies are identified.

  3. Performance comparison — The assessor compares installed capacity vs actual building cooling demand, and checks if controls are optimised for energy efficiency.

  4. Recommendations report — You receive a detailed TM44 report and certificate, which includes:

    • System performance and inefficiencies

    • Faults and repairs needed

    • Control & operational improvements

    • Suggestions for upgrades or replacement if necessary

    • Certificate lodged on the government register

      Note: There’s no legal duty to implement all recommendations — but many of them offer real savings and performance gains.

How Often & What Happens If You Don’t Comply

  • Frequency: TM44 inspections must be carried out at least every five years.

  • First inspection dates: Systems installed after 1 January 2008 must have their first TM44 within five years of use.

  • Legal consequences: If an inspection is overdue or missing, local authorities can impose a £300 fine per system or building.

  • Further fine: You may also be fined £200 if you fail to provide the outstanding inspection report within 7 days of a request.

Why It Matters (Beyond Compliance)

A TM44 inspection is not just a legal tick-box — it’s a tool to optimise your building’s performance:

  • Energy savings & cost reduction — Uncover control inefficiencies, leakage, poor scheduling — many offer low-cost fixes.

  • Carbon & sustainability gains — More efficient operation helps reduce your emissions footprint.

  • Improved lifespan & reliability — Identifying faults early helps prevent breakdowns and extends system life.

  • Informed decision-making — The report gives you clear data to decide whether to upgrade, replace, or optimise controls.

Next Steps & What You Should Do Now

  • Check your HVAC installation documents — find the rated output, age, and service history

  • Check the Landmark Register — see if there’s an existing TM44 certificate lodged for your property

  • Contact an accredited assessor (Level 3 or Level 4) to arrange an inspection

  • Review the report carefully when you get it, and consider implementing low-cost improvements or scheduling bigger upgrades

Let's talk

How can we help you?

From TM44 compliance to identifying potential energy savings, we provide expert support to keep your air-conditioning system efficient and fully compliant.

Email address

tm44@airinspections.co.uk

General enquiries

01335 342445

Headquarters

Optimair Limited, 19 St Christopher's Way, Pride Park, Derby, DE24 8JY

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