10 Reasons Why Your AC Unit Isn’t Blowing Cool Air

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Air conditioning systems are vital to maintaining a healthy and comfortable living environment during the hot season. Their primary function is temperature and humidity regulation. However, cooling systems can experience issues like other mechanical systems. One type of issue we see around this time of year is when an AC unit isn’t blowing cold air. When this occurs, you should take prompt action to prevent discomfort, expensive HVAC repairs, and health hazards.

Be proactive when your AC malfunctions. It will help you ensure optimal HVAC performance, home comfort, and lower energy bills.

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10 Reasons Why Your AC Unit Isn’t Blowing Cool Air

This article lists ten reasons your air conditioner is not blowing cold air. It also includes solutions so they can be resolved quickly.

The Thermostat is Not Set Correctly

woman trying to adjust thermostat

Air conditioners only turn on when the room temperature goes over the control setting. Therefore, ensure that the thermostat is set to AUTO and COOL so that it activates when needed. The first step is to confirm that the programmable thermostat is set to the correct temperature. Occasionally, the problem may happen because the thermostat is set to HEAT instead of COOL.

An accidental adjustment might have happened if your air conditioner was recently serviced. If this is the case, you should switch the thermostat to HEAT before setting it back to cool. Wait several minutes before you check the registers to see if cold air is blowing through.

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Dirty Air Filter

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Make it a habit to check and change your air filters regularly. Otherwise, the dust, dirt, and debris can severely clog them. A clogged air filter impedes the airflow into your home. It can also cause damage to other AC parts, such as the evaporator coil.

A dirty air filter means the airborne particles aren’t filtered out. As a result, you may have a dustier home and experience overall stuffiness, aside from the lack of cold air. Prevent this by checking your air filter monthly. Clean and replace it as needed.

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Dirty or Clogged Condenser Coil

A dirty or clogged condenser coil can result in your central cooling system generating warm air. The condenser fan sucks in air via the condenser coil in the outdoor unit to remove the heat energy from your home during operation. If the coil becomes clogged with airborne particles, dirt, and grass, the airflow between the fins gets obstructed. A dirty condenser unit also reduces the system’s energy efficiency. It can even cause compressor damage or system failure from overuse.

Clean the dust and grime on your condenser coil. You can use a soft brush or a vacuum with a brush attachment to remove the debris from the coil. You can also gently rinse it with a hose. Call a certified HVAC professional to resolve this problem effectively.

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Air Conditioner Refrigerant Leak

image of hvac contractor performing refrigerant refill on air conditioner

A refrigerant leak can also cause your central air conditioning system to not blow cold air. Refrigerant, like R410a, is a crucial substance facilitating the air conditioner’s production of cold air. The coolant goes through the system’s indoor and outdoor coils, transitioning from liquid to gas and vice versa. It absorbs the heat and humidity from the air inside your home and releases it outside.

The system’s refrigerant level usually doesn’t decrease over time unless the refrigerant lines have a leak. When there is a leak, the system won’t have sufficient refrigerant to produce cold air. Keep in mind that it isn’t a good idea to try and repair refrigerant leaks on your own. The Environmental Protection Agency regulates this chemical; only certified experts can handle it. Therefore, leave it in the hands of an HVAC professional as they have the needed tools to find and repair refrigerant leaks. They can also top-up the coolant in your system to maintain the coldness and comfort in your home.

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Mechanical HVAC Problems

Cooling units also go through normal wear and tear as time passes. Therefore, mechanical problems may happen during their lifespan. Understanding how your air conditioner operates can help find and prevent potential mechanical issues from occurring.

Ensure that you check the thermostat and air filter. Contact your trusted HVAC technician immediately if your air conditioner isn’t functioning as expected or not running as long as it should. Book an inspection of your system’s internal parts immediately so you are sure your air conditioner is in good working condition. 

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HVAC Ductwork Leak

ductwork inspection

A leak in the ductwork means the cold air will escape before it reaches the vents. The same will also happen to your heating during the cold seasons.

It is hard to diagnose a ductwork leak. It costs you the cold air you are spending money on. It also requires a lot of money to repair. Call your trusted HVAC technician to resolve this issue.

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Evaporator Coil Issues

The evaporator coil is an indoor component in your air conditioner. It removes the heat and humidity from your indoor air. If your system has low refrigerant levels, the coils can become frozen, and frost can accumulate. This leads to an air conditioner not blowing cold air and increased energy bills.

It can be hard to access the evaporator coil if you aren’t a professional. Therefore, let an HVAC technician handle it.

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Blocked HVAC Vents

image of an hvac vent and hvac airflow issues

A blocked vent can have a similar effect as a clogged air filter. The vents bring air into the system and circulate the cold air to the whole house. Blockages can make it difficult for your air conditioner. 

An obstruction close to the vent will cause the room to feel warmer than other parts of your home. Call a reliable HVAC technician immediately to resolve the problem.

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Undersized AC Unit

Air conditioners are usually sized per their British Thermal Units (BTUs) or cooling capacity. The bad news is that air conditioners that are too small can cause your system to struggle to keep up with your cooling demands as the outdoor temperature rises. Your system ends up working overtime, causing faster wear and tear and, possibly, a premature replacement. 

If your air conditioner is too small, consider installing a ductless mini-split. This can provide cooling to certain hot spots in your home. However, the best solution is to replace your central air conditioner with a unit of the correct size.

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Lack of Regular Air Conditioner Maintenance

Scheduling a tune-up service once a year is the best way to ensure your air conditioner cools your home effectively. Regular AC maintenance will lower your energy costs. It also helps find current and potential problems. 


It can be frustrating when your air conditioner doesn’t function properly, especially when you need it the most. There are many reasons your air conditioner isn’t running as it should. It can be due to simple issues such as thermostat malfunctions or clogged filters. At times, it may be because of complex issues like compressor failure or refrigerant leaks. Leave it to the hands of a certified HVAC technician to diagnose and resolve your cooling issues.

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Lawes Company is the leading provider of heating and cooling services in Monmouth and Ocean Counties, New Jersey. Our team comprises highly skilled and professionally certified technicians specializing in HVAC maintenance, replacements, repairs, and installations. We take pride in delivering exceptional services to all our clients. 

Our company understands the importance of having a comfortable and energy-efficient home. This is why we offer affordable pricing for our services. Our maintenance services are designed to improve comfort and lower energy bills. Our knowledgeable technicians can recommend the best, budget-friendly solutions if you need an HVAC repair or replacement. We stand behind our work and offer a satisfaction guarantee.

Call us today to schedule a service appointment. We offer free, in-home estimates to help you make informed decisions about your HVAC systems. Trust Lawes Company with superior heating and cooling services that will exceed your expectations!

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