Most people only think about their air conditioning when it stops working. By that point, what could have been a routine service call has often become an emergency repair — and an avoidable bill.
Regular servicing is the single most effective thing you can do to keep an air conditioning system running efficiently, reliably, and for as long as possible. This guide covers how often you should be servicing your system, what a service actually involves, and what the signs are that your unit needs attention sooner rather than later.
The Short Answer: How Often Should Air Conditioning Be Serviced?
For most systems, once a year is the minimum recommended service frequency.
For commercial systems, or any unit that runs for extended hours throughout the year, twice a year is the standard recommendation — typically once before the cooling season and once before the heating season if the system provides both functions.
The right frequency depends on a few factors:
- System type. A small residential split system used seasonally has different demands to a commercial VRF system running continuously.
- Usage intensity. The more hours a system runs, the faster components wear and the more frequently filters, coils, and refrigerant levels need checking.
- Environment. Systems installed in dusty, greasy, or high-traffic environments (commercial kitchens, industrial units, retail spaces) will accumulate contamination faster and need more frequent attention.
- Age of the system. Older systems benefit from more regular checks as components become more prone to wear.
If you are unsure what is right for your specific system, contact us today.
Why Regular Servicing Matters
Skipping a service might seem like a straightforward cost saving. In practice, it almost always costs more in the long run.
Energy efficiency drops. A system with dirty filters, blocked coils, or low refrigerant levels has to work harder to achieve the same output. That translates directly into higher energy consumption and higher bills.
System lifespan shortens. Air conditioning equipment is a significant investment. A well-maintained system can last 15 to 20 years. A neglected one may fail well before that, requiring costly replacement rather than a straightforward repair.
Refrigerant leaks go undetected. Refrigerant leaks do not just reduce cooling performance — they carry legal implications under F-Gas regulations. Engineers are required to check for and address leaks as part of a compliant service.
Warranty conditions may be affected. Many manufacturers require evidence of regular professional servicing to honour warranty claims. Skipping services can void cover entirely.
Compliance risk increases for commercial operators. Businesses operating air conditioning systems above certain thresholds have obligations under TM44 and F-Gas regulations. Poorly maintained systems create audit and compliance risk.
What Does an Air Conditioning Service Include?
A professional air conditioning service is not just a filter clean. A thorough service from a qualified engineer covers the following:
- Filter inspection and cleaning. Dirty filters restrict airflow and reduce efficiency. In some environments, filters need cleaning between annual services.
- Coil inspection and cleaning. Both the evaporator and condenser coils are checked for dirt and debris, which reduces heat exchange efficiency.
- Refrigerant level check. Refrigerant is checked to confirm the system is operating at the correct charge. Any shortfall indicates a leak, which must be investigated.
- Electrical checks. Wiring, connections, and components are inspected for wear, corrosion, or loose connections that could cause failure or create a safety risk.
- Condensate drain inspection. Blocked condensate drains cause water leaks and can lead to water damage inside the building. The drain is checked and cleared if necessary.
- Airflow and temperature checks. The engineer confirms the system is delivering the expected airflow and temperature differential across the unit.
- Controls and thermostat testing. All controls, timers, and thermostats are tested to confirm correct operation.
- General condition report. A good engineer will flag any components showing signs of wear that may need attention before the next service.
MGI engineers carry out all of the above and provide full documentation on completion, which is important for businesses managing compliance records.
Commercial Air Conditioning: Higher Demands, More Frequent Servicing
Commercial systems operate under very different conditions to residential units. They typically run for longer hours, serve larger spaces, and are expected to maintain precise conditions regardless of external temperature.
For these reasons, twice-yearly servicing is the standard for commercial air conditioning. Servicing before summer ensures the system is ready for peak cooling demand. A second service before winter prepares it for heating mode and identifies any issues that developed during the summer period.
There are also compliance obligations to consider. Businesses operating air conditioning systems with an output of more than 12kW are required to have a TM44 inspection carried out by an accredited energy assessor every five years. This is separate from routine servicing but sits alongside it as part of a complete compliance picture.
F-Gas regulations impose additional obligations on commercial operators with systems containing fluorinated refrigerants above certain charge sizes. These include mandatory leak checks at set intervals depending on the refrigerant quantity in the system.
Unplanned downtime in a commercial setting carries a cost that goes well beyond the repair bill. A failed system in a retail space, office, data centre, or healthcare environment affects operations immediately. Regular servicing is the most effective way to avoid that scenario.
For businesses managing multiple sites or complex systems, MGI offers planned preventative maintenance agreements that schedule servicing in advance and keep compliance documentation up to date.
Signs Your Air Conditioning Needs Attention Before the Next Service
Sometimes a system needs attention between scheduled services. Do not wait for the next annual visit if you notice any of the following:
Reduced output. If the system is no longer cooling or heating to the level it used to, something has changed. Low refrigerant, dirty coils, or a failing component are common causes.
Unusual noises. Rattling, grinding, hissing, or clicking sounds during operation are not normal. They typically indicate a mechanical issue, debris in the unit, or a refrigerant leak.
Ice on the unit. Ice forming on the indoor or outdoor unit is a sign the system is not operating correctly. Common causes include low refrigerant levels or restricted airflow. Switch the system off and call an engineer.
Water leaks. Water dripping from the indoor unit usually means the condensate drain is blocked. Left unaddressed, this can cause damage to ceilings, walls, and flooring.
Strange smells. A musty smell often points to mould or bacteria growth in the filters or on the coils. A burning smell may indicate an electrical issue and should be treated as urgent.
Higher energy bills without explanation. If your energy consumption has increased but usage patterns have not changed, a poorly performing air conditioning system is a likely contributor.
If you are experiencing any of the above, do not wait for a scheduled service. Contact the MGI team to arrange an inspection.
Frequently Asked Questions
How often should air conditioning filters be cleaned?
For most residential systems, filters should be cleaned every three to six months. In commercial environments or systems operating in dusty or high-traffic areas, monthly checks are advisable. Your service engineer will advise on the right interval for your specific installation.
Does a new air conditioning unit still need servicing?
Yes. A new system still requires annual servicing. Components need checking, refrigerant levels need confirming, and filters need cleaning regardless of how recently the unit was installed. Many manufacturers also require evidence of regular servicing to maintain warranty cover.
What happens if I skip an annual service?
Performance declines, energy consumption increases, and the risk of an unexpected breakdown rises. For commercial operators, skipping a service can also create compliance gaps under F-Gas and TM44 obligations. The cost of an unplanned repair or a compliance issue almost always exceeds the cost of the service that would have prevented it.
Is air conditioning servicing a legal requirement for businesses?
Not in the same direct way that gas safety checks are required for landlords, but commercial operators do have legal obligations that make regular servicing effectively necessary. F-Gas regulations require leak checks at set intervals for systems containing fluorinated refrigerants above certain thresholds. TM44 requires periodic energy inspections for larger systems. Maintaining a service record is the most practical way to demonstrate compliance.
How much does an air conditioning service cost in the UK?
Service costs vary depending on the system type, size, number of units, and location. MGI offers planned maintenance agreements for commercial clients, which fix servicing costs and ensure scheduling is handled in advance. For a specific quote, contact the team or use the MGI price calculator as a starting point for installation cost context.
Keep Your System Running: Book a Service with MGI
Whether you manage a commercial property or have a residential system at home, regular air conditioning servicing is the most cost-effective way to protect your investment and avoid unexpected breakdowns.
MGI’s engineers are F-Gas qualified and work across Oxfordshire and the wider UK. We service all major makes and models, and we provide full documentation on completion — which matters if you are managing compliance records for a commercial site.
To arrange a service or find out more about our planned maintenance agreements, call us on 01865 251225.