What is a TM44 Inspection? (2026) Full TM44 Guide
TM44 Inspections: Is Your Building Legally Compliant in the UK?
Imagine walking into your office on a Monday morning only to find a £300 fine waiting in your inbox — simply for forgetting to conduct a TM44 inspection on your building’s air conditioning system. Yes, unfortunately, it does happen more than you’d think.
Many facility managers treat air conditioning as a "set it and forget it" utility, but if your system has a combined cooling capacity of over 12kW, the law says otherwise. Thankfully, it’s easy to avoid getting hit with that fine once you understand what is required of you as a building owner or facilities manager.
In this blog, we’re going to break down the following questions:
- What is TM44?
- Who needs a TM44 inspection?
- How often do I need a TM44 inspection?
- What are the consequences for ignoring TM44?
Contents
What is the purpose of a TM44 Air Conditioning Inspection?
TM44 is a standard developed by the Chartered Institute of Building Services Engineers (CIBSE) regarding the inspection and reporting of air conditioning systems in the UK, the Republic of Ireland, Malta, and Gibraltar. Put simply, TM44 is a detailed inspection of any air conditioning system with an effective rated output of more than 12kW — it does not apply to air con systems with lower energy outputs.
Although it is mandatory, a TM44 inspection actually benefits business and property owners quite significantly. The job of a TM44 assessor (usually certified through CIBSE) is to identify opportunities for energy savings and spot inefficiencies. By conducting a TM44 survey, building owners often gain invaluable insight into how they can make their systems run more efficiently and reduce their energy expenditure — reducing overheads and aiding sustainability efforts.
Read more on how you can save energy in our HVAC energy savings guide
Who needs a TM44 inspection?
TM44 is a mandatory survey which applies to anyone with an air conditioning system with an effective output of 12kW or more. That includes commercial office spaces, hotels, restaurants, industrial spaces, and more.
Please note that a TM44 inspection is not the same as, nor can it be substituted with, an EPC certificate — these are two separate energy rating certifications. Learn more about the difference between TM44 and EPC.
The inspection is only required every 5 years by law, which isn’t very often. Failure to comply can result in repeated fines of £300, until compliance is proven. Additional fines of £200 can apply if a report is requested by enforcement officers but not provided. Don’t get caught out by that lengthy 5 year window — put the date down in your calendar and get in contact with a certified professional with plenty of time to spare.
Get in contact with a TM44 certified professional today.
How do I know whether I need a TM44 inspection?
The key factor is whether your building’s air conditioning systems exceed the 12kW threshold.
This isn’t based on a single unit, but the combined cooling capacity of all systems within the building. Even if you have several smaller units, they still count towards the total.
For example, if you have:
- Three systems at 5kW each
- Your total capacity is 15kW
In this case, a TM44 inspection is legally required. TM44 applies to a wide range of system types, including:
- Split systems (wall-mounted units commonly found in offices)
- VRF/VRV systems
- Chillers and centralised cooling systems
It also includes both comfort cooling and systems used in areas like server rooms.
If you’re unsure of your system’s output, this information is usually available on the unit itself or within your building’s operation and maintenance manuals. If in doubt, a qualified assessor can help you determine whether you meet the threshold.
What’s included in a TM44 report?
TM44 doesn’t exist just to catch you out — it’s a great opportunity to have a look at how your system can be improved to save you money. Every TM44 post-investigation report should include steps, or a roadmap, on how you can reduce energy expenditure and slash running costs.
Common issues discovered during the TM44 inspection procedure can include:
- Unbalanced systems (too much or too little airflow for the size of the room)
- Poorly optimised operating hours
- Worn, damaged, or blocked components causing reduced airflow and increased resistance (dust-blocked filters and coils are very common)
- Ineffective insulation
At the end of the survey, you will have the knowledge and guidance to tackle these issues, effectively cutting down on your energy usage and enhancing the lifespan of your system via targeted servicing efforts. Understanding your TM44 report and acting on the suggestions is vital to keeping your system running efficiently into the future.
How much does a TM44 inspection cost?
A number of different factors can affect the price of a TM44 inspection, and different companies can offer varied pricing structures. Generally, a small site can expect a TM44 cost of around £400 to £600, with larger properties spending £700 to £1200. Very large companies with multiple air conditioning systems can expect upwards of £1200.
Different sites can host their own challenges which may raise the price of a TM44 inspection. Some assessors may charge extra for system complexity or difficulties in accessing the air conditioners.
That might seem like another frustrating bill to pay, but remember the potential savings in energy expenditure upon completion of a TM44 report. These inspections keep spaces safe for people and also enhance energy efficiency and boost sustainability scores when recommendations are implemented. Therefore, the ROI on a TM44 survey is typically much less detrimental than building owners initially assume.
Note: Always check to make sure your TM44 assessor is properly certified. They must be a qualified air conditioning energy assessor (Level 3 or 4) and registered with an approved accreditation scheme, otherwise the inspection is not valid. ARM Environment’s engineers hold CIBSE TM44 certification —get in touch with us today and steer clear of rogue contractors.
How long does a TM44 inspection take?
Time spent on site can also affect the cost of TM44, as you'll need to pay for labour costs. Small sites may take just a couple of hours, whilst large sites like warehouses can take around a full day. The inspection itself is usually non-disruptive, although access to equipment and plant areas will be required.
Following the site visit, your report is typically delivered within a few working days.
TM44 vs HVAC maintenance: do I need both?
This is a common point of confusion. Regular HVAC maintenance and TM44 inspections serve two very different purposes.
Maintenance focuses on keeping your system running:
- Cleaning filters and coils
- Checking refrigerant levels
- Fixing faults and wear
TM44 inspections are about:
- Legal compliance
- Assessing energy efficiency
- Identifying opportunities to reduce energy use
Even if your system is serviced regularly, you are still legally required to have a TM44 inspection every five years if you exceed the 12kW threshold. That said, a well-maintained system will usually perform better during a TM44 inspection and may result in fewer recommendations.
What happens after a TM44 inspection?
Once your inspection is complete, you’ll receive a detailed TM44 report outlining the assessor’s findings. This report will include:
- An overview of your system and its condition
- Identification of inefficiencies or faults
- Practical recommendations to improve performance and reduce energy use
The report is also lodged on a government-approved register and assigned a reference number. You should keep a copy on file, as you may be asked to provide it during audits or property transactions.
While you are not legally required to act on the recommendations, doing so can lead to noticeable savings in energy costs and improved system performance. Read more on our 2026 energy savings guide.
TM44 Summary - Key Takeaways:
TM44 Inspections aren’t so scary once you understand your responsibilities. Here’s the TM44 breakdown:
- Who: All building owners with a combined cooling capacity of at least 12kW are legally required to have their air conditioning system inspected against TM44
- When: Inspections must be carried out every 5 years
- Why: Non-compliance can lead to repeat fines of hundreds of pounds
- Benefits: Compliance can aid ESG efforts and reduce energy expenditure, reducing overhead costs
We offer professional TM44 Inspections
Don’t let a fine be the reason you find out your air conditioning audit is due. Based in Wiltshire and Hampshire, ARM Environments can attend any site in England and Wales to conduct a professional TM44 survey.
As qualified experts, we help you navigate HVAC compliance while ensuring your systems are running at peak efficiency.
Contact us today to book your TM44 inspection with our CIBSE certified engineers or to discuss how we can improve your building's energy performance.
