The TM44 Compliance Gap: Why Maintenance Records, BMS Data and Energy Bills Often Tell Different Stories

A commercial air-conditioning system can be regularly serviced, free from obvious faults and fully operational—and still consume far more energy than necessary.

This is the compliance gap many building owners and facilities teams fail to see.

The maintenance contractor may confirm that the equipment is running. The building management system may show no critical alarms. Occupants may continue working without a major breakdown. Yet the electricity bills keep rising, certain areas remain too warm or too cold, and the system appears to run for longer than it should.

Each source of information tells part of the story. None of them, on its own, confirms whether the whole air-conditioning system is operating efficiently, correctly controlled or appropriately matched to the building.

That is where a professional TM44 air-conditioning inspection becomes valuable. It does more than confirm whether equipment switches on. It considers how the system is maintained, controlled, operated and used across the building—and whether the available evidence agrees with what is happening on site.

A serviced system is not necessarily an efficient system

Routine maintenance is essential. Filters need cleaning, refrigerant circuits need checking, condensers need inspecting and mechanical faults need identifying before they cause larger problems.

However, maintenance records usually focus on whether individual components are functioning. They may not reveal whether the system is being operated efficiently as a complete installation.

A service engineer may confirm that a fan coil unit is working. That does not automatically mean:

• The operating schedule matches building occupancy.

• The temperature setpoint is appropriate.

• The unit is correctly zoned.

• Heating and cooling are not operating simultaneously.

• The system is not oversized for the current building use.

• Sensors are positioned correctly.

• The controls are communicating properly.

• The equipment is running only when needed.

This distinction is important.

An air-conditioning system can be mechanically healthy but operationally inefficient. It may pass every basic maintenance check while wasting energy every day through poor scheduling, conflicting controls or inappropriate settings.

This is one reason why a planned preventive maintenance contract should not be treated as a substitute for TM44 compliance. Our guide to PPM contracts versus TM44 compliance explains why the two activities serve different purposes.

Maintenance keeps equipment operational. A TM44 inspection examines how effectively the system is being managed and whether its performance could be improved.

Why BMS data can create false confidence

A building management system can provide valuable information. It may show temperatures, operating hours, setpoints, alarms, valve positions, fan speeds and energy trends.

Used correctly, this information can help identify waste and improve control.

The problem is that a BMS only reports what it has been configured to measure.

It does not automatically confirm that:

• Sensors are accurate.

• Time schedules are correct.

• Control logic reflects current occupancy.

• Equipment labels match the physical installation.

• All systems are connected to the BMS.

• Override settings have been removed.

• Faulty components are being reported properly.

• Data is being reviewed by someone who understands it.

A BMS screen can look perfectly normal while the building is still wasting energy.

For example, the system may show a cooling setpoint of 22°C. That appears reasonable. However, if another part of the building is heating the same area to 24°C, the two systems may work against each other without generating an obvious alarm.

The BMS is not necessarily wrong. It is simply showing each instruction separately. The conflict only becomes clear when someone examines the system as a whole.

Another common issue is permanent override. A temporary adjustment may have been introduced during a hot week, a tenant complaint or a change in occupancy. Months later, the override remains active and the system continues running outside the intended schedule.

The BMS may continue reporting normal operation because it is following the overridden instructions exactly.

Energy bills show the outcome, not always the cause

Electricity bills are often the first place a business notices a problem.

A finance team may identify an increase in consumption. A facilities manager may see that summer demand is higher than the previous year. A managing agent may receive questions from tenants about rising service charges.

Energy data confirms that more electricity is being used, but it does not always explain why.

Consumption may increase because of:

• Longer operating hours.

• Higher occupancy.

• Extended opening times.

• New IT equipment.

• Additional air-conditioning units.

• Poorly controlled ventilation.

• Dirty filters or coils.

• Simultaneous heating and cooling.

• Ageing compressors.

• Incorrect temperature settings.

• Faulty sensors.

• Increased cooling demand following refurbishment.

• Tenant-installed systems not included in the original controls strategy.

The energy bill is therefore an important warning signal, but not a diagnosis.

To understand the cause, the building team must compare the bill against the equipment, controls, maintenance history, operating patterns and actual use of the property.

This is where the TM44 inspection process can help connect the evidence.

The three versions of the same building

In many commercial properties, there are effectively three different versions of the air-conditioning system.

The first version exists in the maintenance file.

This may contain service sheets, refrigerant records, equipment schedules and defect notes. It represents what the contractor has inspected and recorded over time.

The second version exists in the BMS.

This is the digital version of the building: sensors, schedules, setpoints, alarms and control points.

The third version exists physically on site.

This is the real installation, including additions, replacements, temporary systems, disconnected units, tenant alterations, inaccessible equipment and undocumented changes.

Problems arise when these three versions no longer match.

The maintenance schedule may list 24 indoor units while 29 are actually installed. The BMS may control only 20 of them. The energy bills may reflect all 29.

No single record is necessarily complete.

A good TM44 inspection brings these separate sources together and compares the documentation with the physical installation.

The hidden importance of an accurate asset register

An air-conditioning asset register should provide a clear record of what is installed, where it is located and how it forms part of the wider system.

In practice, asset registers are often incomplete or outdated.

Common problems include:

• Missing model numbers.

• Duplicate equipment references.

• Units listed in the wrong area.

• Decommissioned equipment still shown as active.

• New systems omitted after refurbishment.

• Indoor units recorded without associated outdoor units.

• Equipment capacities missing.

• Tenant installations excluded.

• Plant labels that no longer match the documentation.

These gaps matter because the total effective cooling output helps determine the compliance position of the building.

A series of smaller systems may appear insignificant when reviewed individually. When combined, they may bring the building within the scope of the relevant inspection requirements.

Our guide to the air-conditioning asset register for a TM44 inspection explains what information is useful and how an incomplete register can affect quoting, inspection planning and the accuracy of the final report.

An assessor can still inspect a building where documentation is limited, but better information usually leads to a more efficient site visit and a clearer understanding of the installation.

Case study: the serviced office that never switched off

Consider a multi-storey office building with a formal maintenance contract, a functioning BMS and no significant mechanical failures.

The maintenance records showed that the VRF systems were serviced twice a year. Filters had been cleaned, indoor units were functioning and no serious refrigerant issue had been recorded.

The BMS showed stable temperatures and no critical alarms.

Despite this, the building’s electricity consumption remained unusually high outside normal working hours.

A review of the operating schedules identified that several floors were running until 11:00 pm every weekday. The building was usually almost empty after 7:00 pm.

The reason was not a mechanical fault. An extended schedule had been introduced months earlier to accommodate a temporary project team. The schedule was never reset.

The maintenance contractor had no reason to report a defect because the equipment was working exactly as instructed. The BMS did not trigger an alarm because the schedule was valid. The energy bill showed the cost, but not the cause.

The improvement required no major replacement programme. The controls were corrected, the out-of-hours operation was reduced and a formal process was introduced for reviewing temporary overrides.

This is a useful example of why operational review matters as much as component condition.

Case study: simultaneous heating and cooling in a refurbished floor

A commercial floor was refurbished and divided into smaller meeting rooms and offices. Additional split systems were installed to manage the new internal loads.

The original central system remained active.

Occupants complained that some rooms felt cold while adjacent areas felt warm. The local split systems were regularly adjusted by staff, often down to very low temperatures. At the same time, the base building system continued supplying heat according to its original zoning strategy.

Both systems were operational. Neither had failed.

However, one system was heating while the other was cooling.

The maintenance reports focused on individual equipment condition. The BMS covered the base building system but not all tenant-installed units. The electricity bills showed increasing consumption following the refurbishment.

The issue only became clear when the installation, controls and building use were considered together.

The appropriate response was not simply to replace equipment. It was to review the zoning, setpoints, control responsibility and interaction between landlord and tenant systems.

This is why refurbishment creates a significant compliance and performance risk. Our article on TM44 risk after commercial refurbishment explains how changes to layout, occupancy and cooling provision can undermine the original system strategy.

Case study: an old chiller blamed for the wrong problem

A building owner assumed that an ageing chiller was responsible for high energy consumption.

The plant was more than 15 years old, so replacement appeared to be the obvious solution. Budget estimates were obtained for a major capital project.

Before proceeding, the wider system was reviewed.

The chiller was old, but the larger problem was elsewhere. The chilled-water system was operating for long periods at low demand. Several control valves were not responding correctly, and the building schedule had not been adapted following a reduction in occupancy.

The plant was therefore producing cooling when only a small part of the building required it.

The eventual improvement plan prioritised controls, valve repairs and recommissioning before replacement.

This did not mean that the chiller would never need replacing. It meant that the business could make the capital decision using better evidence.

The distinction between repair, recommissioning and replacement is explored in our guide: Repair, recommission or replace commercial air conditioning?

The best decision is not always the most expensive one. It is the one supported by evidence.

What a TM44 inspection adds to the picture

A TM44 inspection is not a destructive test and it is not the same as a full engineering design review. However, it provides a structured assessment of the air-conditioning system and its operation.

Depending on the building and available information, the inspection may consider:

• The type and arrangement of installed systems.

• Effective cooling capacity.

• Equipment condition.

• Maintenance arrangements.

• Control settings and time schedules.

• Temperature setpoints.

• Zoning.

• Occupancy patterns.

• System sizing.

• Opportunities to improve efficiency.

• The quality of available documentation.

• Whether the installed system reflects the asset records.

• Whether the system appears suitable for the current use of the building.

The assessor’s role is not simply to produce another certificate. The purpose is to identify practical opportunities to improve how the system is managed.

For building owners who are unfamiliar with the process, our detailed guide to what happens during a TM44 inspection explains how the survey is typically carried out and what information may be requested.

Why “no alarms” is not the same as “good performance”

Facilities teams often rely heavily on alarms.

This is understandable. Alarms are designed to highlight failures, extreme conditions or values outside predefined parameters.

However, energy waste does not always generate an alarm.

A system running two hours longer than necessary may still operate within normal limits. A setpoint of 19°C may be unnecessarily low but not technically invalid. A sensor may be slightly inaccurate without crossing the fault threshold. A poorly zoned area may remain uncomfortable without any component failing.

Many inefficiencies are therefore silent.

They do not stop the system from operating. They simply increase cost, reduce comfort or shorten equipment life over time.

This is one reason high energy use can continue for years without a clear technical failure being recorded.

The role of occupant complaints

Occupant complaints are often dismissed as subjective, but they can be useful evidence.

Repeated complaints about hot and cold areas may indicate:

• Poor zoning.

• Draughts.

• Incorrect sensor location.

• Overcooling.

• Inadequate airflow.

• Control conflicts.

• Changes in occupancy.

• Heat gains that were not considered in the original design.

• Local units operating against central systems.

One complaint may not prove a technical issue. A pattern of similar complaints across time and location can be significant.

Facilities managers should record complaints in a structured way rather than treating each one as an isolated event.

Useful information includes:

• Date and time.

• Location.

• Outdoor conditions.

• Room occupancy.

• Reported temperature.

• Whether local controls were adjusted.

• Whether the issue is recurring.

• Whether it occurs at a particular time of day.

This type of evidence can help the assessor understand how the system performs in real use.

Why maintenance contractors, energy managers and assessors may reach different conclusions

These professionals often examine the same building from different perspectives.

A maintenance contractor may focus on condition, faults and reliability.

An energy manager may focus on consumption patterns, tariffs, carbon reporting and operational cost.

A controls specialist may focus on BMS logic, sensors, schedules and system integration.

A TM44 assessor considers how these elements relate to the air-conditioning inspection requirements and the overall efficiency of the installation.

Different conclusions do not necessarily mean that one party is wrong.

The problem is often that each party has access to a different part of the evidence.

The strongest approach is collaborative. Maintenance records, BMS trends, energy data and site observations should be reviewed together.

What facilities managers should prepare before an inspection

Good preparation does not need to be complicated.

The most useful information usually includes:

• The current air-conditioning asset register.

• Previous TM44 report, where available.

• Maintenance records.

• F-Gas documentation where relevant.

• BMS access or operating schedules.

• Known faults.

• Refurbishment history.

• Details of tenant-installed equipment.

• Energy consumption data.

• Site plans.

• Contact details for someone familiar with the building.

Not every building will have every document. A missing asset list does not automatically prevent an inspection.

Our guide to TM44 inspections without an asset list explains how the process can still move forward and what alternative information may help.

The objective is not to create paperwork for its own sake. It is to give the assessor enough context to understand the installation accurately.

Turning the final report into an action plan

The report should not be filed away and forgotten.

The most useful next step is to convert the recommendations into a practical improvement plan.

A sensible approach is to group actions into three categories.

Immediate operational changes

These may include:

• Correcting time schedules.

• Resetting inappropriate temperatures.

• Removing unnecessary overrides.

• Aligning controls with occupancy.

• Ensuring doors and windows are managed properly in conditioned areas.

• Reviewing out-of-hours requests.

These changes are often low cost and can be implemented quickly.

Maintenance and recommissioning actions

These may include:

• Cleaning coils or filters.

• Repairing sensors.

• Rebalancing airflow.

• Checking valves and actuators.

• Reviewing control sequences.

• Recommissioning zones.

• Correcting BMS points.

• Updating equipment labels and records.

These actions require technical input but may still be far less expensive than plant replacement.

Capital improvements

These may include:

• Replacing obsolete equipment.

• Improving controls.

• Installing variable-speed drives.

• Reconfiguring systems.

• Replacing inefficient chillers.

• Upgrading high-consumption plant.

• Improving heat recovery.

Capital actions should be prioritised using evidence, expected savings, remaining equipment life and operational risk.

For a more detailed explanation of what recommendations mean, read our guide to TM44 report recommendations.

The service-charge issue

In multi-let commercial buildings, inefficient cooling can become a service-charge problem.

Tenants may see rising costs but have limited visibility over how the central system is controlled. Landlords may rely on maintenance reports showing that equipment is operational. Managing agents may struggle to explain why electricity use has increased.

A TM44 report can help create an independent evidence base.

It can support discussions about:

• Operating schedules.

• Shared plant.

• Tenant alterations.

• Responsibility for local equipment.

• Control improvements.

• Capital expenditure.

• Energy-saving measures.

• Long-term replacement planning.

Our article on TM44 and commercial property service charges explores this issue in more detail.

The value is not only compliance. It is clarity between the parties responsible for operating and paying for the building.

Portfolio buildings need consistent evidence

For organisations with multiple properties, the compliance gap can be multiplied across an entire portfolio.

Different buildings may use different maintenance contractors, BMS platforms, asset-register formats and energy-reporting systems. One site may have excellent records while another has almost none.

Without a consistent process, senior management cannot easily compare:

• Which sites have valid reports.

• Which systems are approaching renewal.

• Which buildings have incomplete asset data.

• Which sites have unusually high cooling consumption.

• Which recommendations remain outstanding.

• Which buildings present the greatest operational risk.

A centralised approach to TM44 portfolio management helps owners and managing agents build a consistent compliance record across multiple sites.

This is particularly important for national businesses, schools, healthcare organisations, retail chains and property-management portfolios.

TM44 is not only about legal compliance

The legal requirement is the reason many businesses first investigate TM44.

However, the operational value can be greater than the certificate itself.

A well-conducted inspection can help a business:

• Understand what equipment is actually installed.

• Identify control weaknesses.

• Improve maintenance priorities.

• Investigate energy waste.

• Support budget planning.

• Reduce unnecessary operating hours.

• Improve occupant comfort.

• Prepare for plant replacement.

• Strengthen its compliance records.

• Create clearer responsibility between landlords, tenants and contractors.

The inspection does not force a business to replace every old unit. It provides information that supports better decisions.

That is the real value of closing the compliance gap.

How TM44.uk can help

TM44.uk provides accredited air-conditioning inspections for commercial buildings across the UK.

We support:

• Offices and corporate headquarters.

• Retail properties and shopping centres.

• Schools and colleges.

• Healthcare buildings.

• Hotels and leisure facilities.

• Industrial and manufacturing sites.

• Public-sector buildings.

• Multi-site property portfolios.

• Managing agents and facilities-management companies.

• Landlords and commercial tenants.

Our service includes the site inspection, preparation of the report, certificate and required lodgement.

We can also review the information available before attendance and advise what documentation would be useful. Where an asset list is incomplete, we can help establish what is needed to provide an accurate quotation and plan the inspection correctly.

For a formal quotation, use our TM44 inspection quote form. You can provide the property address, site details and any available asset information.

Businesses that are unsure whether their installed cooling capacity exceeds the threshold can use our TM44 kW checker as an initial guide.

You can also check the wider compliance position using the TM44 compliance checker.

Final perspective

Maintenance records, BMS data and energy bills are all valuable.

The mistake is assuming that any one of them provides the complete answer.

Maintenance records may confirm that equipment is operational. BMS data may show that the controls are issuing instructions. Energy bills may reveal that consumption is rising.

A TM44 inspection helps connect those facts.

It compares documentation with the physical installation, considers how the system is controlled and operated, and identifies practical opportunities to improve efficiency.

In many buildings, the largest savings are not hidden inside a failed compressor. They are hidden in schedules, setpoints, zoning, overrides, undocumented equipment and operating habits that nobody has reviewed for years.

Closing the TM44 compliance gap means moving beyond the question, “Is the air conditioning working?”

The better question is:

Is it working efficiently, appropriately and in a way that reflects how the building is actually used?

That is the question the evidence must answer.