When the first hot week hits London, the same thing happens across offices and hospitality sites. Meeting rooms in Shoreditch turn into ovens, a restaurant dining area in Soho gets complaints, or a hotel corridor in Canary Wharf starts feeling humid and stale.
Most of the time, the system did not suddenly fail. It has been struggling for weeks. Filters have loaded up, condensate drains have started to block, refrigerant has leaked slowly, or control settings have drifted after a tenant change.
This article is a practical guide for commercial clients across areas like Stratford, Greenwich, Hammersmith, Wembley, Ealing and Croydon. It explains what “servicing” should include, what documentation you should keep and how to build a maintenance routine that prevents breakdowns and keeps compliance tidy.
What “air conditioning servicing” actually means
A proper service is not just a quick clean and a sticker. In commercial buildings, servicing is part of a wider planned preventative maintenance (PPM) approach where maintenance is performed purposefully and regularly to keep plant and equipment in satisfactory operating condition.
For air conditioning, that usually means:
restoring airflow and heat transfer so the system can actually cool properly
reducing strain on compressors and fans so you avoid failure under peak load
identifying early warning signs and planning fixes before they become outages
keeping the paperwork that proves you have a maintenance system in place
Inspection, servicing and compliance are not the same thing
Facilities teams often get caught out because these terms are mixed together in quotes.
Servicing and PPM
This is the day to day maintenance that keeps the system reliable. It is what prevents faults.
TM44 inspections
A TM44 air conditioning inspection is a specific requirement under the Energy Performance of Buildings rules. GOV.UK guidance states that systems with an effective rated output of more than 12kW must be inspected and inspections must be no more than five years apart.
TM44 is about energy efficiency and assessment, not hands on servicing. It is separate from your ongoing maintenance plan.
F gas leak checks
If your system contains fluorinated refrigerants, there are separate obligations around leak checking and repair. GOV.UK sets out leak check frequency based on CO2 equivalent thresholds, including annual checks for 5 to less than 50 tonnes CO2e and 6 monthly checks for 50 to less than 500 tonnes CO2e.
These checks sit alongside servicing and should be planned into your programme.
Why offices and hospitality sites fail first in summer
Here are the most common reasons commercial systems struggle when demand spikes.
Filters and airflow get ignored
As filters load up, airflow drops. That reduces cooling and increases strain on the system. In hospitality venues, the problem is worse because doors open constantly and footfall is high.
Condensate drainage blocks
A partly blocked drain can trigger alarms, overflow into ceilings, or cause shutdowns. You usually see this first in heavily used areas like bar back rooms, kitchens and comms cupboards.
Refrigerant leaks go unnoticed
Small leaks often show up as “it takes longer to cool” before they become “it does not cool at all”. If your system falls into the leak check thresholds, you must follow the required frequency.
Controls drift after changes
After refurbishments or tenant changes, schedules and setpoints are often left wrong. This is a major cause of comfort complaints in offices and wasted energy in mixed use buildings.
Nobody owns the evidence
The work might be happening but the records live in emails. When procurement, insurers or auditors ask, it becomes a scramble.
What a proper service visit should include
You can use the list below to compare contractors and to check whether your current visits are genuinely useful.
1) System condition and performance checks
A service should confirm the unit is operating correctly, not just running.
Expect:
temperature split checks across return and supply air
visual checks for oil staining or corrosion
checks for unusual noise or vibration
checks for alarms and fault history
2) Filters, coils and airflow
This is where most “cooling problems” start.
Expect:
filter inspection and replacement as needed
coil inspection and cleaning where required
fan and airflow checks at key points
What to log:
filter type and change date
coil condition notes
any airflow restrictions and actions taken
3) Condensate and drainage
This prevents shutdowns and building damage.
Expect:
condensate tray inspection
drain line inspection and flush where needed
checks for evidence of overflow or staining
What to log:
drain condition
any blockages cleared
any leak risk areas identified
4) Electrical checks inside the system
Air conditioning failures often start as electrical issues.
Expect:
checks of isolators and terminals for heat damage signs
checks of contactors and relays where accessible
checks of control wiring condition
basic safety checks around enclosures
5) Refrigerant circuit checks
This is where competence matters.
Expect:
checks that indicate potential undercharge or performance loss
checks for visible signs of leakage
confirmation of whether your system is in scope for formal leak check frequencies
GOV.UK summarises how leak check frequency depends on the amount of F gas and its CO2 equivalent thresholds.
6) Controls and scheduling review
A good contractor will check that the system matches occupancy.
Expect:
schedule review for office hours or trading hours
zone control checks, especially for mixed use areas
advice on reducing simultaneous heating and cooling where relevant
TM44 guidance notes that inspection reports can include advice on controls and maintenance adequacy, which is exactly why keeping controls sensible matters.
The simplest servicing schedule that prevents most breakdowns
Most commercial portfolios get the best results from a seasonal approach.
Pre summer service
This is your most important visit. The aim is to be ready before peak load.
Focus:
filters, coils and airflow
condensate drains
performance checks under cooling demand
controls and schedules
Mid season check for high demand sites
For hospitality venues, gyms and higher footfall buildings, a mid season check can prevent repeat callouts.
Focus:
filter condition
drain checks
quick performance verification
fault trend review
Pre winter review
Many systems are heat pumps, and even if you are not using heating heavily, a pre winter check helps reset controls and catch issues.
This sits nicely inside a PPM approach which RICS describes as maintenance performed purposely and regularly to keep building services in satisfactory operating condition.
What to log so procurement and audits are painless
You do not need a complex CAFM system to start. You need consistent records.
Create one log per site that includes:
asset register: unit IDs, locations and type (split, VRF, AHU)
visit reports: what was checked, what was found, what was done
defects list: priority, target date, completion evidence
refrigerant records and leak check schedule where required
TM44 report reference and next due date if the system is over 12kW
The reason this works is simple. It proves you run a system, not random callouts. That is what retainer clients need.
Common mistakes we see in London commercial sites
“We serviced it” meaning no documented checks and no measurable outcomes
Filters replaced but coils ignored so efficiency still drops
Condensate issues left until there is a ceiling leak
Controls never reviewed after a refurb in Southwark or a tenant change in Canary Wharf
TM44 due dates missed because nobody owns the diary
F gas leak checks treated as optional even when thresholds apply
What a good retainer looks like for air conditioning
If you want fewer emergencies, a retainer should include:
scheduled servicing visits aligned to your risk and usage
a clear defects and remedials process
priority response options for critical failures
consistent reporting across all sites
reminders for TM44 where relevant and refrigerant leak check scheduling where required
This is how you turn AC from a summer panic into a managed building service.