Tenant-Installed Air Conditioning and TM44 Compliance Risk

Tenant-installed air conditioning can create one of the most overlooked TM44 compliance risks in commercial buildings. A landlord may believe a property is compliant. A managing agent may have service records for the main plant. A tenant may assume their own split system is too small to matter. But once additional air conditioning units are installed inside a commercial building, the total cooling capacity can change, and that can affect whether a TM44 inspection is required.

This issue is common in offices, retail units, restaurants, salons, clinics, gyms, serviced offices, workshops and multi-let commercial buildings. It usually happens quietly. A tenant takes a lease, carries out a fit-out, installs comfort cooling or server-room cooling, and the landlord’s original compliance file is never updated. Years later, the property is sold, refinanced, re-let, audited or reviewed by a facilities manager, and nobody can clearly confirm whether the building has a valid TM44 certificate.

That is the risk.

TM44 compliance is not only about the original landlord-installed air conditioning. It is about the air conditioning systems serving the commercial building and whether the combined cooling output triggers the legal requirement. If tenant-installed AC pushes the total above the relevant threshold, or if the building was already over the threshold and the tenant adds more equipment, the compliance position needs to be reviewed.

For landlords, tenants and managing agents, the safest approach is simple: do not assume tenant-installed air conditioning is outside the TM44 requirement. Check the asset list, check the cooling capacity, check the lease position, and confirm whether the property has a valid lodged TM44 report.

Why Tenant-Installed Air Conditioning Creates a Hidden TM44 Problem

The hidden problem is ownership and visibility.

In many commercial buildings, not all air conditioning is controlled by one party. A landlord may own the central plant, roof condensers or common area systems. A tenant may install split units, cassette units, wall-mounted systems, comms-room cooling or supplementary cooling as part of their own fit-out. A managing agent may hold maintenance records for landlord systems but have limited visibility over tenant alterations.

That creates a compliance gap.

The building may have started below the threshold. Then one tenant adds two wall-mounted split systems. Another tenant adds cooling to a server room. A retail tenant adds additional cassettes because the shopfront overheats in summer. A dental practice installs surgery cooling. A restaurant adds extra cooling to the customer area. Individually, each unit may look small. Combined, the building’s effective cooling output may now be over 12kW.

This is why the air conditioning over 12kW TM44 requirement matters. TM44 is not only triggered by one large chiller or one large VRF system. Multiple smaller units can matter when they serve the same commercial building or site.

The issue becomes more serious because tenant-installed AC is often missing from the asset register. It may not appear in the landlord’s compliance pack. It may not be included in the planned preventative maintenance contract. It may not be visible in the old TM44 report. It may not be declared before a sale, lease renewal or service charge review.

That is where disputes and compliance problems start.

The 12kW Threshold and Why Small Units Can Still Matter

A common mistake is to look at each air conditioning unit in isolation. A landlord or tenant might say, “This split system is only 5kW, so TM44 does not apply.” That may be wrong if there are multiple systems in the building.

For example:

• Tenant A installs one 5kW split system in a small office.
• Tenant B installs one 7kW cassette system in a meeting room.
• The landlord already has two small common-area systems.
• A comms room has an additional cooling unit.

Individually, these may not look like a major plant installation. Together, they may create a TM44 requirement.

This is why we recommend checking the total cooling capacity, not just the largest individual unit. If the capacity is unclear, use the TM44 kW checker or ask for a technical review before assuming the building is outside scope.

Tenant-installed systems are especially easy to miss because they often arrive after the original fit-out. The landlord may have had a clean compliance position at the start of the lease, but that position can change when tenants alter the cooling systems.

The highest-risk buildings are usually:

• Multi-let office buildings
• Serviced offices and coworking spaces
• Retail parades and retail parks
• Restaurants, cafés and commercial kitchens
• Medical, dental and cosmetic clinics
• Gyms and fitness studios
• Server rooms and IT-heavy offices
• Light industrial and mixed-use commercial sites
• Refurbished buildings where tenants control their own fit-outs

If you are unsure whether the building is over the threshold, read our guide on how to check the TM44 12kW threshold.

Who Is Responsible: Landlord, Tenant or Managing Agent?

Responsibility depends on the lease, the control of the building, the ownership of the equipment and the practical ability to arrange compliance. But from a risk-management point of view, all three parties should care.

The landlord should care because the building’s compliance position can affect property transactions, lease events, buyer enquiries, investor due diligence, refinancing, insurance questions and asset management records.

The tenant should care because tenant-installed air conditioning may create maintenance obligations, reinstatement obligations, lease compliance issues or contribution disputes. If a tenant installs AC without properly recording system details, they may create future problems during assignment, lease renewal, exit or dilapidations.

The managing agent should care because they often coordinate building compliance, maintenance records, service charge administration and contractor access. If the building is later found to have no valid TM44 report, the agent may be asked why the AC asset list was incomplete.

For more on this topic, see our guide on landlord, tenant and managing agent TM44 responsibility. The key point is that TM44 should not be left in a grey area. Somebody needs to confirm the system capacity, whether a valid report exists, and whether the inspection covers the actual systems now installed at the property.

The Multi-Tenant Building Risk

Multi-tenant buildings are where this issue becomes more complicated.

In a single-tenant building, it is usually easier to identify all air conditioning systems. The occupier controls the space, the landlord can ask direct questions, and the maintenance contractor may have one clear asset list.

In a multi-tenant building, the AC picture can be fragmented. Each tenant may have different equipment, different maintenance contractors, different access restrictions and different records. One tenant may have inherited equipment from a previous occupier. Another may have installed new equipment during a fit-out. A third may have disconnected old units without removing them from the roof. The landlord may hold common-part records but not the full tenant demises.

This matters because TM44 compliance is weakened when the inspection is based on an incomplete asset list.

If a previous TM44 report was completed before tenant alterations, it may not fully reflect the current building. If the report only covered landlord-controlled plant, it may not include tenant-installed systems that are now part of the cooling load. If the landlord cannot identify which systems exist and who owns them, the inspection process becomes slower and more expensive.

Managing agents should therefore maintain a live AC schedule for multi-let buildings. This does not need to be complicated, but it should include:

• Tenant name or unit reference
• System make and model where available
• Indoor unit locations
• Outdoor condenser locations
• Cooling capacity in kW
• Installation date if known
• Maintenance contractor details
• F-Gas records where applicable
• Whether the system is landlord-owned or tenant-owned
• Whether access is needed through a tenant demise, roof area, riser or plant space

This information helps an assessor quote accurately, inspect efficiently and avoid missing systems.

For portfolio landlords and agents, our TM44 portfolio management service can help organise multiple properties, track renewal dates and reduce the chance of missed compliance.

Example Case Study: The Office Building That Looked Compliant

A managing agent was preparing a compliance file for a multi-let office building. The landlord had an older TM44 report on file and assumed the building was covered. On paper, the landlord-controlled air conditioning had been inspected several years earlier.

During a lease renewal review, one tenant mentioned that they had installed additional cooling in a boardroom and comms cupboard. Another tenant had also installed a small split system in a rear office after complaints about overheating. These systems were not included in the old asset register.

The issue was not that the tenant had necessarily done something wrong. The issue was that the building’s compliance file no longer matched the actual building.

The agent had to gather the updated AC details, check whether the total cooling capacity had changed, confirm what systems were present and arrange a fresh review. The landlord then had a clearer position before lease renewal and avoided a last-minute problem with the tenant and solicitor.

The lesson is direct: tenant-installed air conditioning should be treated as a compliance trigger, not just a fit-out detail.

This kind of scenario also links with wider commercial property risk. A missing or outdated TM44 position can become a problem during sale, refinance, lease renewal or due diligence. We explain this further in our guide to TM44 commercial property deal risk.

Tenant Fit-Outs: What Should Be Checked Before Approval?

Before a landlord approves tenant-installed air conditioning, there should be a basic compliance check. This does not need to slow down the deal, but it should prevent future confusion.

Before approval, ask:

• What type of AC system is being installed?
• What is the make and model?
• What is the cooling capacity in kW?
• Where will indoor units be located?
• Where will outdoor condensers be located?
• Will the system connect to any landlord plant, roof space or risers?
• Who will maintain the system?
• Will the tenant provide commissioning certificates and F-Gas details?
• Does the installation affect the building’s existing TM44 position?
• Should the system be added to the landlord’s AC asset register?

If the tenant cannot provide the kW output, the model numbers can usually be used to identify capacity. If the building is already near the threshold, even a small installation may be enough to trigger a review.

This is particularly important after refurbishment. Tenants often improve comfort cooling during fit-out, especially in older commercial buildings. Read more about this in our guide on TM44 risk after commercial refurbishment.

Why Service Charge Can Become an Issue

Tenant-installed AC can also create service charge questions.

If a TM44 inspection is required because tenant systems form part of the building’s total cooling capacity, the landlord or managing agent may need to decide how inspection costs are handled. This depends on the lease and the structure of the building. Some costs may sit with the landlord. Some may be recovered through service charge. Some tenant-specific costs may be recharged directly if the lease allows it.

The problem usually arises when records are poor. A tenant may say the inspection is a landlord compliance cost. The landlord may say the tenant’s own equipment created the need for further inspection. The managing agent may be stuck in the middle with incomplete records.

The best way to reduce this risk is to keep the AC asset register current and clear. If the building has landlord systems and tenant systems, identify both. If tenant systems create additional inspection complexity, record this early. If the service charge position is unclear, check the lease before arranging works.

For more detail, see our article on TM44 service charge for commercial property.

What Documents Should Landlords and Managing Agents Request?

A strong TM44 compliance file should not rely on guesswork. If tenants have installed air conditioning, landlords and managing agents should request the correct information and store it properly.

Useful documents include:

• AC asset list
• Make and model numbers
• Cooling capacity details
• Installation date
• Commissioning certificate
• F-Gas records where applicable
• Maintenance records
• Tenant alteration licence or fit-out approval
• Roof or plant access notes
• Photos of indoor and outdoor units
• Previous TM44 report if one exists
• Confirmation of whether the system is still operational

If there is no proper asset list, do not wait until the next transaction. Read our guidance on arranging a TM44 inspection with no asset list. In many cases, an assessor can still help, but the quote and inspection process will be cleaner if basic information is available.

A good asset list also helps avoid missed systems. Hidden systems are common in comms rooms, back offices, basement areas, retail stockrooms, small plant rooms and roof spaces. See our guide on hidden TM44 air conditioning systems for more examples.

When Should You Book a TM44 Inspection?

You should consider booking a TM44 inspection when:

• The building has air conditioning systems with combined cooling output over 12kW
• A tenant has installed additional AC and the total capacity is unclear
• The previous TM44 report has expired or may not cover current systems
• A lease renewal, assignment, sale or refinance is approaching
• A managing agent is building a compliance file
• A buyer, tenant, solicitor, lender or auditor has asked for TM44 evidence
• The building has undergone refurbishment or tenant fit-out works
• The AC asset list has changed since the last report
• Multiple tenants control separate cooling systems
• The landlord wants to reduce compliance risk before marketing the property

If you are not sure whether the property needs an inspection, start with a basic review. Use the TM44 checker or send the available asset information for assessment. If a report is already lodged, the building’s status may also need to be checked against the TM44 register.

What Happens During the Inspection?

A TM44 inspection is designed to assess the efficiency, sizing, controls, maintenance and general performance of qualifying air conditioning systems. The assessor reviews the installed systems, available records and site conditions, then produces a lodged report with recommendations.

For tenant-installed systems, access planning matters. The assessor may need to inspect indoor units inside tenant spaces and outdoor units on roofs, walls, yards or plant areas. If systems are spread across multiple demises, the managing agent should coordinate access in advance.

A good inspection process normally includes:

• Review of AC asset information
• Site access planning
• Visual inspection of relevant AC systems
• Review of controls and operation where possible
• Review of maintenance information
• Assessment of sizing and efficiency issues
• Identification of improvement recommendations
• Production and lodgement of the TM44 report
• Delivery of the certificate/report pack to the client

If you want to prepare properly, read our guide on what we need from you for a TM44 quote. The better the information provided at the start, the faster the quote and inspection can be arranged.

The Energy Cost Angle: Not Just Compliance

Many businesses treat TM44 as a legal box to tick. That is a mistake. Tenant-installed AC can also create energy waste.

Common issues include:

• AC and heating running against each other
• Poor control settings
• Units left operating outside occupancy hours
• Old systems serving low-demand areas
• Oversized cooling in small rooms
• Poorly maintained filters and coils
• Duplicate systems installed because the original system was poorly understood
• Server-room cooling left unmanaged
• Tenant systems running separately from landlord controls

These issues may not always create immediate enforcement problems, but they can increase electricity costs and reduce building efficiency. A useful TM44 inspection can highlight practical recommendations that help the landlord, tenant or managing agent improve performance.

That is why TM44 should be seen as part compliance, part building intelligence. A proper inspection gives you a clearer picture of what is installed, where energy is being used and what should be improved.

If your building has high energy use, old cooling equipment or uncertain records, you may also want to review post-inspection improvement options through an energy efficiency upgrade report.

The Commercial Lease Problem Nobody Wants at the Last Minute

Tenant-installed air conditioning becomes most painful when it is discovered late.

Examples include:

• A buyer’s solicitor asks for the TM44 report during due diligence.
• A tenant asks whether their installed AC is included in the building compliance file.
• A lender requests evidence of statutory compliance.
• A managing agent changes and discovers missing asset records.
• A landlord prepares a service charge budget and realises AC compliance has not been reviewed.
• A tenant exits and the landlord finds old AC units still installed but not recorded.
• A refurbishment uncovers disconnected or undocumented cooling systems.

At that point, everyone wants the answer quickly. Does the building need a TM44 inspection? Is the old report still valid? Does it cover the tenant systems? Who pays? Can access be arranged? Are systems still operational? Is there enough information to quote?

This is why early review is better than last-minute firefighting.

If a commercial property is being sold or leased, TM44 should be checked alongside EPC, F-Gas, maintenance records, asbestos, fire safety and other compliance documents. It is a small item compared with the value of a transaction, but it can cause avoidable delays when ignored.

How TM44.uk Helps Landlords, Tenants and Managing Agents

TM44.uk helps commercial property owners, tenants, facilities managers and managing agents understand whether a TM44 inspection is required and arrange inspections across the UK.

We can assist with:

• Reviewing whether tenant-installed air conditioning may trigger TM44
• Checking whether the building appears to be over the 12kW threshold
• Advising what information is needed before quotation
• Reviewing old reports and asset lists
• Arranging inspections for single sites or portfolios
• Coordinating access with landlords, tenants and site contacts
• Producing and lodging TM44 reports through accredited assessors
• Helping clients understand recommendations and renewal dates

If the building is urgent, we can also support time-sensitive enquiries where a landlord, buyer, tenant or managing agent needs a fast compliance position. For urgent situations, see our emergency TM44 service.

For multi-site landlords, retail groups, office portfolios and managing agents, the best approach is not to wait until each report expires. A proper portfolio tracker allows you to monitor sites, renewal dates, old reports, asset lists and inspection priorities before they become urgent.

Practical Checklist Before You Ask for a Quote

Before requesting a quote for a property with possible tenant-installed air conditioning, gather as much of the following as possible:

• Full property address and postcode
• Building type, such as office, retail, clinic, gym or restaurant
• Number of tenants or commercial units
• Any existing AC asset list
• Make and model of systems where available
• Cooling capacity in kW if known
• Previous TM44 report if available
• Maintenance records
• F-Gas records where applicable
• Floor plans or unit layout if available
• Access restrictions
• Contact details for tenants or site manager
• Preferred inspection timescale
• Any sale, lease, audit or deadline date

Do not worry if you do not have everything. Many clients come to us with incomplete information. The key is to start the review early enough so the missing details can be identified before they cause a delay.

You can request a quote through TM44.uk and include any information you already have. If the building has tenant-installed AC, mention this clearly in the enquiry so it can be considered from the beginning.

Final Advice for Landlords and Managing Agents

Tenant-installed air conditioning is not just a fit-out detail. It can change the compliance position of a commercial building. It can affect whether a TM44 inspection is required. It can create uncertainty during lease events, sales, refinancing, service charge discussions and compliance audits.

The safest approach is to keep a live AC asset register, require tenants to provide installation details, check the 12kW threshold, and ensure the building has a valid TM44 report where required.

If you own, manage or occupy a commercial building and are unsure whether tenant-installed AC has created a TM44 requirement, do not guess. Check the system capacity, check the records and get the position confirmed.

TM44.uk can help you review the situation, identify what information is missing and arrange a compliant inspection where required.

Call 0203 811 8331 or request a quote online through TM44.uk.