AC Repair London

Expert Air Conditioning Repair in London

When your air conditioning stops working, you need a fast, reliable repair from engineers you can trust. London AC Pro provides professional AC repair services across all 32 London boroughs, with same-day appointments available for urgent breakdowns. Our F-Gas certified and REFCOM Elite registered team (company reg 15526897) diagnoses and repairs all major air conditioning brands including Daikin, Mitsubishi Electric, Samsung, LG, Fujitsu, Toshiba, Panasonic, Hitachi and more. Whether your home AC has stopped cooling, your office unit is leaking water, or your commercial system is showing error codes, we have the expertise and parts to get you back up and running quickly.

Air conditioning problems rarely happen at convenient times. A system that fails on the hottest day of summer or stops heating during a cold snap is more than an inconvenience — it can affect your health, sleep, productivity and business operations. That is why we offer same-day repair appointments where possible and aim to complete the majority of repairs on the first visit. Our engineers carry a comprehensive stock of common spare parts, so there is often no need to wait for parts to be ordered.

Common AC Problems We Diagnose and Repair

Our engineers have seen and fixed every conceivable air conditioning fault. Here are the most common problems London homeowners and businesses encounter:

AC Not Cooling or Heating Properly

If your system is running but not reaching the desired temperature, common causes include low refrigerant due to a leak, dirty or blocked filters restricting airflow, a failing compressor, a faulty expansion valve, or incorrect thermostat settings. Our diagnostic process identifies the root cause quickly, and we provide a clear explanation and repair quote before starting any work.

Strange Noises from the AC Unit

Air conditioning systems should operate quietly. Unusual sounds typically indicate specific faults: rattling or vibrating suggests loose panels, mounting brackets or fan blades; buzzing may indicate electrical issues or a failing contactor; clicking can signal a faulty relay or control board; grinding often points to a worn fan motor bearing; and hissing might indicate a refrigerant leak. Our engineers diagnose noise issues accurately and carry out repairs to restore quiet, efficient operation.

Water Leaking from the Indoor Unit

Water dripping from your indoor AC unit is one of the most common calls we receive. In the vast majority of cases, the cause is a blocked condensate drain. As warm, humid air passes over the cold evaporator coil, moisture condenses and drips into a drain tray, flowing away through a small pipe. Over time, this drain can become blocked with algae, dust or debris, causing water to overflow from the tray and drip from the unit. Our engineers clear the drain, clean the tray and can install a condensate pump if the drainage route is problematic.

Bad Smells When the AC Runs

Musty, stale or unpleasant odours from your AC unit usually indicate mould, bacteria or biological growth on the evaporator coil or in the drain tray. This is particularly common in systems that have not been serviced regularly. A thorough deep clean with specialist anti-bacterial products resolves the issue and restores fresh, clean air. In some cases, a full service and deep clean is the most effective solution.

AC Not Turning On or Displaying Error Codes

If your AC will not turn on at all, common causes include a tripped circuit breaker, a blown fuse, a faulty control board, a wiring fault or a failed compressor. Modern AC systems from Daikin, Mitsubishi Electric, Samsung and other brands display specific error codes that help our engineers identify the fault quickly. If your unit is flashing an error code, note it down and share it when you call us — this can speed up diagnosis.

Frozen Evaporator Coils

Ice forming on the indoor evaporator coil or refrigerant pipes usually indicates low refrigerant (often due to a leak), severely restricted airflow from dirty filters, or a faulty fan motor. Running the system in this condition can cause further damage, so we recommend turning it off and calling for a repair.

Remote Control or Wi-Fi Issues

Problems with remote controls, wall controllers or Wi-Fi connectivity can often be resolved without a physical repair visit. However, if basic troubleshooting does not work, our engineers can diagnose and resolve control issues, replace faulty remote receivers and reconfigure Wi-Fi connections.

AC Tripping Electrics

If running your AC causes the circuit breaker to trip, this is a potentially dangerous electrical fault that should be investigated promptly. Common causes include a compressor earth fault, a short circuit in the wiring, a failed capacitor or water ingress to electrical components. Do not repeatedly reset the breaker — call for a professional diagnosis.

All Brands Repaired

We repair all major air conditioning brands including:

• Daikin — including Emura, Stylish, Perfera, FTXS, FAQ, VRV and all commercial ranges
• Mitsubishi Electric — including Zen, M-Series, Mr Slim, City Multi VRF and all residential and commercial units
• Samsung — including Wind-Free, standard wall-mounted, cassette, ducted and DVM VRF systems
• LG — including Artcool, Standard Plus, Multi V VRF and all commercial units
• Fujitsu — including ARSTG, ASYG, Airstage VRF and all residential and commercial ranges
• Toshiba — including Seiya, Shorai, Haori, Super Digital Inverter and SMMS VRF systems
• Panasonic, Hitachi, Carrier, Midea and other manufacturers

For more information about the brands we work with, visit our brands page.

Our AC Repair Process

We have designed our repair process to be as straightforward and transparent as possible:

• Call or book online — contact us on 07301 010244 or request a repair online. Describe the symptoms and, if possible, share any error codes displayed on the unit.
• Diagnostic visit — our F-Gas certified engineer visits your property, carries out a thorough diagnostic assessment and identifies the fault. The diagnostic fee starts from £99 and is deducted from the repair cost if you proceed with the repair.
• Transparent quotation — once the fault is identified, we explain the issue in plain language and provide a clear, written quote for the repair. You know exactly what you are paying before any work begins. There are no hidden charges.
• Expert repair — most repairs are completed on the first visit. Where specialist parts need to be ordered, we prioritise sourcing and schedule the follow-up visit at the earliest opportunity.
• Testing and commissioning — after the repair, we fully test the system to verify it is operating correctly, check refrigerant levels if applicable, and run a performance check.
• 12-month guarantee — all repair work is covered by our 12-month guarantee on both parts and labour, giving you complete peace of mind.

Repair vs Replace — Honest Advice

We will always give you honest, straightforward advice on whether repairing your AC system is worthwhile or whether replacement makes better financial sense. As a general guideline, we may recommend considering replacement if:

• The system is over 10 to 12 years old and uses an older, less efficient refrigerant such as R410A (as newer R32 systems are significantly more efficient)
• The repair cost exceeds 40 to 50 per cent of the cost of a new system
• The system has required multiple repairs in the past 12 months
• The unit is significantly less energy efficient than modern equivalents
• Spare parts are becoming difficult to source or discontinued

If replacement is the better option, we will provide a clear quotation for a new residential or commercial installation and credit your diagnostic fee against the new installation cost.

Emergency AC Repairs

For urgent breakdowns that cannot wait for a standard appointment — such as a complete system failure during a heatwave, a commercial system down affecting business operations, or a server room cooling failure — we offer emergency AC services with rapid response times. Maintenance plan customers receive priority emergency response.

Frequently Asked Questions About AC Repair

How quickly can you repair my AC?

We offer same-day appointments where available and aim to attend within 24 hours for standard repair requests. Most repairs are completed on the first visit. For emergencies, our emergency service offers rapid response times. Call 07301 010244 for the next available appointment.

How much does an AC repair cost?

Our diagnostic visit starts from £99, which is deducted from the repair cost if you proceed. The total repair cost depends on the fault and parts required. Minor repairs such as a blocked drain or faulty capacitor are typically £100-£250. More significant repairs such as a control board replacement or refrigerant leak repair range from £250-£600. We always provide a clear, written quote before starting any repair work.

Do you guarantee your repair work?

Yes. All AC repairs carried out by London AC Pro are covered by a 12-month guarantee on both parts and labour. If the same fault recurs within 12 months, we will return and rectify it at no additional cost.

Can you repair my AC if another company installed it?

Absolutely. We repair all brands and all installations, regardless of who originally installed the system. Our engineers are trained and experienced on Daikin, Mitsubishi Electric, Samsung, LG, Fujitsu, Toshiba and all other major manufacturers.

My AC is showing an error code — what should I do?

Note down the error code displayed on your indoor unit, remote control or wall controller. You can share this with us when you call on 07301 010244, and our engineers can often provide initial guidance over the phone. Error codes vary by brand and model, so having the exact code helps us prepare for your diagnostic visit with the right parts and information.

Is it worth repairing an old AC system?

It depends on the age of the system, the nature and cost of the repair, and the efficiency of the existing unit compared to modern alternatives. As a rule of thumb, if the repair cost exceeds 40-50% of a new system and the unit is over 10 years old, replacement often makes better long-term financial sense. Our engineers will always give you honest advice on the best course of action.

Do you carry spare parts on your van?

Yes. Our engineers carry a comprehensive stock of common spare parts including capacitors, fan motors, PCB boards, sensors, filters and drain pumps. This means many repairs can be completed on the first visit without waiting for parts to be ordered.

Can you repair commercial AC systems?

Yes. We repair all types of commercial air conditioning systems including VRF/VRV, cassette, ducted, wall-mounted and floor-standing units in offices, hotels, restaurants, retail and all other commercial environments across London. For businesses with critical cooling needs, we also offer planned maintenance contracts to minimise the risk of unexpected breakdowns.