If your AC is running but not cooling, the problem usually occurs due to dirty air filters, low refrigerant levels, a faulty compressor, frozen coils, or thermostat issues. Each of these problems can disrupt the cooling process, causing your home to feel warmer even though the system appears to be functioning properly.
Fortunately, many of these problems are easy to identify once you know what to look for. In this guide, we’ll cover the most common reasons your AC isn’t cooling and help you figure out whether a simple fix or professional repair is needed to get your home comfortable again.
For a prompt repair service, contact Season Control Heating & Air Conditioning at 818-275-8487. Our HVAC professionals are available 24/7 in Los Angeles and surrounding areas.
1. Dirty or Clogged Air Filter
A dirty or clogged air filter is one of the most common reasons an air conditioner struggles to cool your home. The air filter traps dust, dirt, and other particles to protect air conditioners and improve indoor air quality. When the filter becomes clogged, it restricts airflow, making it difficult for the system to distribute cool air throughout the house.
Restricted airflow can cause the evaporator coil to freeze, further blocking the cooling process. It also forces the air handler to work harder, which can lead to overheating and unnecessary wear on the system. Over time, this can put stress on other components, such as the condenser unit and condenser coils.
If you notice weak airflow or your AC is running but not cooling, checking the air filter should be your first step. Ideally, changing the filter every 1–3 months can prevent these issues and keep your central air system running smoothly.
2. Refrigerant Leak
Low refrigerant levels are another common reason your air conditioner may run but not produce enough cold air. Refrigerant absorbs heat from the inside of your home. If there’s a refrigerant leak, the AC can’t cool the air properly, and you may notice longer run times or weak airflow.
Signs of a refrigerant leak include:
- Hissing sounds near your outdoor unit
- Ice buildup on the refrigerant lines
- Warm air coming from the vents
- Increased energy bills without a change in AC usage
If you experience any of these symptoms, contact an HVAC professional promptly. Avoid DIY AC troubleshooting as handling refrigerant issues requires special equipment and certification.
3. Bad AC Compressor
A bad compressor can cause your air conditioner to run without delivering cold air. The compressor circulates refrigerant between the evaporator coil and the condenser unit. When it malfunctions, the AC unit loses its ability to cool your home.
Common signs of a failing compressor include loud noises from your outdoor unit, short cycling, or the system struggling to maintain a comfortable temperature. This can result in higher energy bills and increased strain on other components of the AC system.
If your air conditioner shows signs of a faulty compressor, professional AC repair can prevent further damage. Continuing to run a system with a bad compressor can put additional stress on the condenser coil and may lead to complete system failure.
4. Frozen Evaporator Coils
The evaporator coil is responsible for absorbing heat from inside your home. When the coil freezes, it blocks the cooling process, causing your AC to blow warm air instead of cold.
A frozen evaporator coil can occur due to restricted airflow from a dirty air filter, low refrigerant levels resulting from a refrigerant leak, or malfunctioning parts, such as the air handler. If airflow is blocked, the temperature around the coil drops too low, allowing moisture to freeze on its surface.
Signs of frozen evaporator coils include:
- Ice buildup on the indoor coil or refrigerant lines
- Weak or no airflow from vents
- Water leaking around the indoor unit when the ice melts
Running your AC system with frozen coils can cause severe damage to the condenser unit and its coils. It also reduces overall air quality and increases the strain on the central air system.
If you suspect a frozen evaporator coil, turn off your AC unit and schedule a professional AC repair. An HVAC professional can diagnose the issue, check for underlying problems, and restore proper cooling performance.
5. Electrical Problems of the AC Unit
Electrical issues such as faulty capacitors, damaged wiring, or malfunctioning relays can prevent key parts of your AC unit, like the compressor or condenser fan, from operating correctly. When these components fail, your system may struggle to complete the cooling process, resulting in warm air blowing from the vents.
Signs of electrical problems include:
- Air conditioner frequently trips the circuit breaker
- Outdoor unit not turning on, even though the indoor fan is running
- Unusual clicking or buzzing noises from the outdoor unit
- AC system short cycling (turning on and off rapidly)
- Uneven cooling or sudden loss of cold air
Because electrical repairs involve high voltages and delicate components, it is essential to avoid DIY fixes. Instead, contact a qualified HVAC professional near you to inspect and repair the system safely.
6. Dirty or Blocked Condenser Fan and Coil
The condenser coil is responsible for releasing the heat absorbed by the evaporator coil. If dirt, debris, or grass clippings clog the condenser coils or block the condenser fan, your air conditioner struggles to expel heat.
When the condenser unit cannot release heat, the entire AC system works harder, leading to reduced cold air output and increased wear on the system.
Signs of a dirty or blocked condenser fan and coil include:
- Warm air blowing from vents despite the AC running
- Unusual noises coming from your outdoor condenser unit
- Air conditioner running longer cycles without effectively cooling
- Noticeable overheating around your outdoor unit
Routine AC maintenance, like clearing debris from the condenser unit and scheduling regular professional cleanings, can help prevent these issues.
However, if you suspect your outdoor unit is dirty or blocked, it’s best to call your local HVAC company to clean the system and restore performance.
7. Incorrect Thermostat Settings
Sometimes, the reason behind your AC not cooling is as simple as incorrect thermostat settings. If the thermostat is set to “fan” instead of “cool,” the air conditioning system will circulate air without actually cooling it.
Other thermostat issues include a malfunctioning sensor or improper placement of the thermostat itself. If the thermostat is located near a heat source, such as a window or appliance, it can misread the room temperature, causing the air conditioner to operate inefficiently.
If adjusting your thermostat settings doesn’t solve the problem, contact an HVAC technician to inspect the thermostat and the system.
8. Ductwork Leaks
If there are holes, cracks, or disconnected sections in your duct system, a large amount of cold air can escape before it reaches your living spaces. As a result, the air conditioner is unable to maintain the set temperature, resulting in warm rooms and inconsistent cooling.
Signs of ductwork leaks include:
- Uneven temperatures throughout the house
- Weak airflow
- Higher energy bills without increased AC usage
- Dustier indoor air than usual
Poorly sealed or damaged ducts reduce cooling efficiency and strain your air conditioning system, resulting in increased wear and tear over time. If you suspect duct issues, contact your nearby HVAC contractor to seal and repair the leaks.
Restore Cold Air in Your Home With Our AC Repair Service
At Season Control Heating & Air Conditioning, we specialize in diagnosing and resolving all types of cooling issues, ensuring your air conditioner delivers the cold air you need.
Our certified HVAC professionals provide 24/7 emergency AC repair services for all major brands and models of air conditioners. We are committed to fast response times, friendly customer support, and high-quality workmanship that keeps homes across Canoga Park and surrounding areas cool and comfortable.
If you notice signs of poor cooling, don’t wait for the problem to worsen.
Call 818-275-8487 for a professional AC repair you can count on.
FAQs
Why is my AC not cooling even though it’s running?
An AC not cooling could be caused by dirty air filters, low refrigerant levels, electrical problems, or issues with the compressor. It’s important to identify the root cause early to prevent bigger system failures.
What steps should I take for AC troubleshooting before calling a technician?
Basic AC troubleshooting includes checking your thermostat settings, inspecting the air filter, ensuring the outdoor unit is clear of debris, and verifying that the circuit breaker hasn’t tripped. If the AC still doesn’t cool, it’s time to call a professional.
How does a dirty condenser coil affect my air conditioner’s performance?
A dirty condenser coil prevents the system from releasing heat properly, making it harder for your air conditioner to cool your home. Over time, this can lead to overheating, system strain, and even higher energy bills.
Can issues with my AC system cause higher energy bills?
Problems within your AC system, such as refrigerant leaks, frozen evaporator coils, or worn-out parts, force the unit to work harder, resulting in reduced efficiency and higher monthly energy costs.
What’s the difference between a regular AC unit and a central air conditioning system?
A central air conditioning system cools your entire home through a network of ducts, providing even temperatures throughout all rooms. In contrast, a regular AC unit, such as a window or portable unit, typically cools only one room or a small area.
What should I do if your outdoor unit is making strange noises?
If your outdoor unit is making unusual noises, such as buzzing, rattling, or clicking, it may indicate issues with the fan motor, condenser coils, or electrical components. It’s best to turn off the system and contact an HVAC professional to inspect and repair the problem.
