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Common Air Conditioner Problems and Troubleshooting Tips


Air conditioners are essential appliances that keep our homes cool and comfortable, especially during hot summer months.  However, like any other device, they can encounter problems from time to time.

Understanding and troubleshooting common issues can save you from discomfort and potentially costly repairs. Here, we will explore common air conditioner problems and how to prevent and troubleshoot them. 

What are the Most Common Air Conditioner Problems?

Common Air Conditioner Problems and Troubleshooting Tips

Air conditioners are a lifeline during scorching summer days, providing a cool retreat from the sweltering heat. However, like any complex machinery, they can encounter problems. Here are some of the most common problems air conditioning systems experience:

Poor Air Flow

Poor cooling performance is one of the most common air conditioning problems. An air conditioning system that experiences this issue produces less cool air than usual. This common problem can be attributed to several factors. 

One primary culprit is dirty or clogged air filters, which restrict the airflow and reduce the system’s efficiency. Additionally, a blocked or obstructed condenser unit can hinder the heat exchange process, making it harder for the air conditioner to cool the air. Low refrigerant levels due to a refrigerant leak are another potential cause, as insufficient refrigerant can compromise the system’s cooling capacity.

Regularly cleaning or replacing dirty filters and ensuring the condenser unit is free from obstructions are crucial to addressing these common AC issues and providing enough air for your needs. You may also need to hire an HVAC expert for professional maintenance or repair to fix and check your AC and help add refrigerant to your air conditioning units.

Strange Noises

Unusual sounds emanating from your air conditioner can be disconcerting and often indicate underlying issues. Loose or damaged parts within the AC, such as belts or bearings, can generate strange noises during operation.

Additionally, debris in the outdoor unit, such as leaves or twigs, can cause rattling or clunking sounds. Addressing these issues may involve tightening or replacing loose parts and ensuring the unit is debris-free. If the noises persist, consulting an HVAC technician for a thorough inspection is advisable.


Discovering water leakage around your air conditioner can be attributed to various factors. A clogged or disconnected drain line can impede the proper drainage of condensate, leading to water accumulation.

A frozen evaporator coil can also cause water leakage as it thaws. Improper installation, which includes inadequate insulation and positioning, may contribute to condensation issues. Clearing drain lines, defrosting evaporator coils, and ensuring correct installation are key steps to resolve water leakage problems.

Air Conditioner Not Turning On

A malfunctioning air conditioner that refuses to turn on can stem from different causes. A tripped circuit breaker is a common culprit, disrupting the power supply to the unit. A faulty thermostat may prevent the system from receiving the appropriate signals to start or maintain the desired temperature.

Issues with capacitors or compressors, critical components regulating electrical flow, and refrigerant compression can also lead to failure. Troubleshooting involves checking and resetting the circuit breaker, ensuring the thermostat sensor is correct, and consulting a professional for capacitor or compressor issues.

Uneven Cooling

Uneven cooling throughout your living space is a frustrating problem with multiple potential causes. Blocked or closed vents impede the proper distribution of cooled air, leading to temperature disparities. Insufficient insulation in certain areas can contribute to uneven cooling, allowing heat to infiltrate.

Damaged ductwork may also hinder the airflow, exacerbating the problem. Ensuring all vents are open and unobstructed, improving insulation, and repairing damaged ductwork are essential to achieve consistent cooling.

Foul Odors

Unpleasant odors emanating from the AC can result from various sources. Mold or mildew growth within the system or on the evaporator coils can produce musty smells. Accumulated dirt in the ducts can release unpleasant odors when the breeze circulates.

In extreme cases, dead animals or insects within the unit may cause foul smells, and a burning smell may mean a wiring issue. Regular cleaning of air filters, scheduling professional duct cleaning, and thorough inspections can help identify and eliminate the sources of these odors and help you achieve cold air without the smell.

Constant Cycling On and Off

A malfunctioning AC that cycles on and off too frequently can be attributed to several factors. Dirty or frozen evaporator coils compromise the heat exchange, causing the system to overheat and shut down.

An overworked compressor, often a result of blocked vents or low refrigerant levels, can lead to frequent cycling. Incorrect thermostat settings may also cause the system to start and stop abruptly. Additionally, worn-out bearings or belts can contribute to the constant cycling issue.

Regular maintenance, cleaning coils, addressing airflow issues, adjusting thermostat settings behind the control panel, and replacing worn components are crucial to resolving this problem. 

What are Common Fixes for an AC That’s Not Working?

When your AC malfunctions, figuring out the exact reasons behind the issues can be frustrating. However, troubleshooting common air conditioning problems can often provide insights and help you address the malfunction. Let’s explore how to troubleshoot your AC problems when issues arise.

Poor Cooling Performance

When faced with poor cooling performance, start by maintaining the efficiency of your AC. Regularly clean or replace dirty air filters to ensure optimal airflow and prevent dust and debris buildup. 

Additionally, check the area around the condenser unit for any obstructions, such as overgrown vegetation or debris, which can hinder the heat exchange process. Usually, doing this fixes any common air conditioning problems. If this does not work, there may be an underlying problem that you need to fix. 

For a more comprehensive approach, schedule professional maintenance at regular intervals. A qualified technician can inspect the entire system, identify any issues, and recharge refrigerant levels if necessary, ensuring your air conditioner operates at its best.

Remember always to maintain your unit to prevent worse issues like compressor failure.

Strange Noises

If your air conditioner is producing unusual sounds, a systematic approach to troubleshooting is crucial. Begin by inspecting the unit for loose or damaged parts. Tighten or replace any components as needed to eliminate potential sources of noise. Clearing the area around the unit of debris, such as leaves or twigs, can also help in minimizing rattling or clunking sounds.

Should the noises persist, it’s advisable to seek the expertise of a professional technician. Their thorough inspection can pinpoint the exact cause of the noise, whether it’s a worn-out component or a more complex issue within the system.


Common AC problems like water leakage around your air conditioner should be a cause for concern. Water leaks or leaking ducts demand prompt attention. Start by checking the drain line for clogs and clearing them if necessary to ensure proper drainage. 

Confirm that your air conditioner is correctly installed and adequately insulated to prevent condensation issues leading to water leakage. Check your evaporator coil if it’s frozen; you can thaw the coils using warm air or a blower fan to fix this issue. You should also regularly clean your coils.  

A technician can assess the installation, identify potential leaks, repair the AC problem, and provide solutions to prevent further water damage.

Air Conditioner Not Turning On

When your air conditioner refuses to turn on, a systematic troubleshooting process can help identify and address the issue. Begin by checking the circuit breaker and resetting it if necessary, ensuring a stable power supply to the unit.

Make sure your thermostat is set to the desired temperature and functioning correctly. If these steps don’t resolve the problem, it’s advisable to consult an HVAC technician for a more in-depth diagnosis. They can identify electrical issues, assess the thermostat’s functionality, and examine components like capacitors and compressors for potential faults.

Refrigerant Leak

If you suspect that you have refrigerant leaks from your refrigerant lines, it’s a serious issue that can cause serious AC problems. You should consult a professional who could help in adding refrigerant and fix the existing problems on your AC system. 

They can match the manufacturer’s specifications regarding refrigerant charge and even system failure. A technician can assess the installation, identify potential leaks, and provide solutions to prevent further water damage.

Uneven Cooling

Addressing uneven cooling requires a targeted approach to enhance the overall performance of your air conditioner. Ensure all vents are open and unobstructed to facilitate air coming from the AC throughout your living space. Improve insulation in areas experiencing temperature disparities to prevent heat infiltration.

For a comprehensive solution, engage a professional technician to inspect and repair any damaged ductwork. You can achieve a more balanced and consistent cooling experience in every room by addressing these issues.

Foul Odors

Unpleasant odors from your air conditioner can be resolved with proactive maintenance. Clean or replace your dirty air filter regularly to eliminate mildew or mold growth, which can cause musty smells. Schedule professional duct cleaning to remove accumulated dirt, preventing odors from circulating through your home.

If something smells like rubber burning inside, there might be some wiring issues. Stop using it immediately and turn off your circuit breakers.  A rotten egg smell usually indicates a gas leak. 

If foul odors persist, consult a technician for a thorough inspection. They can identify hidden issues within the system, such as the presence of dead animals or insects, and provide appropriate solutions.

Constant Cycling On and Off

If your AC is cycling on and off too frequently, targeted troubleshooting can help restore proper functionality. Begin by cleaning or defrosting the evaporator coils, as dirt or ice buildup can disrupt the heat change process. Check and adjust thermostat controls to ensure they align with your comfort preferences.

If the issue persists, consult a professional technician for a more in-depth inspection. They can identify underlying issues such as overworked compressors or worn-out components, providing solutions to prevent continuous cycling and maintain efficient operation.

Faulty Thermostat

A malfunctioning thermostat can prevent your AC from turning on or maintaining the desired temperature, resulting in less cold air or hot air. This can lead to discomfort and uneven cooling in your living space.

Ensure your thermostat is set to the correct temperature. If the problem persists, consider replacing or recalibrating the thermostat.

What Fails the Most in an AC Unit?

Capacitors and compressors are critical components in an air conditioning unit responsible for regulating the flow of electricity and the compression of refrigerant. Over time, these parts can wear out or fail, leading to various AC malfunctions.

Regular professional maintenance can identify and address issues with capacitors and compressors before they result in a complete breakdown. Timely replacements can extend the life of your AC unit.

Why is My AC Running But Not Cooling?

Inadequate refrigerant amount can hamper the cooling capacity of your air conditioner. Common signs include reduced cooling efficiency, ice buildup on the evaporator coils, and a constant running of the AC without achieving the desired temperature.

To fix, schedule a professional inspection to identify and fix refrigerant leaks. Once repaired, the refrigerant levels should be properly topped up to restore your AC’s cooling efficiency.


Understanding common air conditioner problems empowers homeowners to address issues promptly, ensuring a comfortable indoor environment.

Remember that most common AC issues can be mitigated with regular maintenance, a clean air filter, timely troubleshooting, and professional inspections. These are key to keeping your AC unit in top-notch condition.

By taking these proactive measures, you can prolong your AC unit and enjoy consistent cooling performance even during the hottest days of the year.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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