Even if you have a top air conditioner, you should know what to do when your AC isn’t cooling. While air conditioning repair can seem stressful, most issues shouldn’t require an AC repair technician. You can usually fix your cooling problem with routine air conditioning cleaning and maintenance. So, before you toss out your air conditioning unit, read this troubleshooting guide on what to do when your AC is not cooling. The most common problems relating to cooling will come from needing to clean your vents or filters, condenser coil on a central unit, or checking to make sure the AC has enough coolant.


  • If your AC isn’t cooling, ensure that your air filters and air vents are clean.
  • Clean the dirty condenser coils with soap and water, but do not get the top of the outdoor unit wet.
  • Check your system for a refrigerant leak, and contact a professional to check the refrigerant levels.

Luckily, there are multiple common air conditioner problems that you can fix at home with basic AC knowledge. For example, finding the right size AC filter ensures the proper airflow in your home, controlling the indoor temperature. In addition, a dirty air filter can make your AC system get hot.

Why Is My AC Not Blowing Cold Air?

An air conditioner unit full of hot air can cause sleepless nights or uncomfortable days, but you can fix most minor issues with some routine maintenance. While you shouldn’t need a professional technician, ask for help if you have a truly broken air conditioning unit. So, before we call an air conditioning service, let’s do some basic troubleshooting.

Insider Tip

Consider reaching out for AC repair if you feel uncomfortable looking at the internal parts of the air conditioning unit.

Clean Vents

Air flow is critical to the cooling power of your AC unit. If your vents are covered with hair, dirt, or dust, the AC system will struggle to fill your home with cold air. Use a vacuum or dusting wand to clean your vents.

Change Your Air Filter

Your AC system needs a clean air filter to catch airborne particles and allergens. That said, some air filters are too dense for your system, and they restrict the airflow. Change the filters regularly to keep the unit energy efficient.


Do not use a pressure washer to clean your outdoor AC unit with soap and water, as the powerful stream can damage the AC unit.

Clean Outdoor Unit

If you have a central AC system, you should ensure that the outdoor condenser unit is clean and unobstructed. If trees or bushes are near your outdoor AC unit, bits of plant and dirt can get stuck in the condenser coil. Use regular dish soap and a hose to clean the condenser, but only spray the sides.

Check for a Refrigerant Leak

Check your refrigerant lines for leaks. Refrigerant helps your system absorb indoor heat and pass it outside. Over time, the refrigerant may leak, leading to diminished cooling ability. If you suspect a leak, contact a service professional to check your refrigerant levels.

STAT: According to Energy Star, if your air conditioning unit or heat pump is over ten years old, you should install a new model for energy efficiency. (source)

Finding out what’s wrong with your air conditioning system is essential for your energy bills and a comfortable summer or winter. Whether your central air conditioner stops working at night or there’s mold in your window unit’s outdoor system, you need AC service.

For users concerned about energy efficiency, read our guide to setting your central air conditioning for when you’re away.


Can I reset my AC?

Most systems do not have a button for a complete system shutdown, but you can perform a similar process by turning off the circuit breaker that connects to the unit. While this isn’t recommended for your central air conditioning system, it is the safest first step to diagnosing issues.

Why is my air conditioner not turning off?

The most common cause of an AC system not turning off is poor airflow. If your air ducts aren’t clean and your AC unit cannot efficiently pass cool air into the home, it will run longer to hit the target temperature. That said, other serious issues can cause your system to run continuously.

How do I know if my AC compressor is bad?

If you have trouble starting your AC system or it won’t get cold enough, you may have a compressor malfunction. In addition, a faulty compressor unit will cause loud noises and vibrations to come from your AC system.

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