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Why is My Air Conditioner Blowing Hot Air?

Gas leak

An air conditioner blowing warm air is no fun, especially when you’re expecting some cool relief on a hot day. It’ll no doubt leave you thinking, “Why is my air conditioner blowing hot air?”

There’s often a variety of potential reasons behind the problem. Nevertheless, when your air conditioner isn’t cooling right, it affects your whole home. But many of these can be fixed with some troubleshooting or some routine air conditioning maintenance.

Let’s look at some common reasons why you might find your AC blowing warm air when you least need it to.

The Thermostat Setting Isn’t Right

One of the first things to check when your air conditioner is blowing warm air is the thermostat settings.

There’s every chance you may have accidentally switched the thermostat to ‘heat mode’ or set it to ‘fan setting only’. It’s easy to do. Either will likely have your AC blowing hot air instead of cool air.

You might be able to fix the problem simply by making sure you’ve set the thermostat to ‘cool’ and the fan to ‘auto’. If the settings are correct and you’re still not getting cool air then it might be worth booking an AC system service and checking for other problems. A simple setting adjustment might be all you need!

A vent in the ceiling for a ducted reverse cycle air conditioning system.

Airflow Obstructions and Ductwork

Airflow obstructions and ductwork issues can also make your air conditioner blow warm air.

Blocked or damaged air ducts will reduce the volume of cooled air that reaches your living spaces, leaving you with warm airflow instead of cool. Other factors that can disrupt the airflow of your system include:

  • debris
  • dust build-up or
  • damage to the ductwork

Leaks in the ductwork will also allow cool air to escape before it reaches the vents. Consistent duct cleaning and checks for any obstructions or damage are the simplest and most effective ways to maintain proper airflow.

By keeping your ducts clear and functioning properly, you’ll keep your air conditioning system running smoothly and cool your home with ease.

A Dirty or Clogged Air Filter

Air conditioners need clean filters to deliver optimal performance throughout your home. A clogged or dirty air filter is one of the most common reasons why AC systems blow hot air.

When air filters get clogged with dust and debris, they restrict air flow which means your air conditioning system can’t circulate cool air properly. These sorts of blockages can cause your AC unit to overheat and blow warm air through your vents.

To avoid this, conduct a regular air filter check and replace them if they’re dirty. Regular maintenance of your air conditioning system, including clean air filters, will help to keep proper airflow and your AC blowing cold air.

Refrigerant Leaks or Low Refrigerant Levels

This one shouldn’t happen too often, but low refrigerant levels or refrigerant gas leaks can be another reason why your air conditioner is blowing hot air.

For any Heating, Ventilation and Air Conditioning (HVAC) system that provides cooling to your home, refrigerant is essential. Its purpose is to absorb heat from the air and facilitate the cooling process. When your system experiences a refrigerant leak, your air conditioning system can’t cool properly and warm air will come out of the vents or indoor unit. Low levels of refrigerant gas can also cause other problems like frozen evaporator coils.

If you suspect a refrigerant leak, call a HVAC professional technician as this is not a DIY fix. A leaking refrigerant line can be dangerous and will affect your AC unit’s overall performance.

A Dirty or Frozen Evaporator Coil

A frozen or dirty evaporator coil will stop your air conditioner from cooling properly. It’ll leave you with warm air instead of the cold airflow you want.

The evaporator coil absorbs heat from indoor air. However, when you have a dirty coil, or it’s become frozen due to poor airflow or low refrigerant, the coil becomes incapable of doing its job. A frozen coil restricts the cooling process and your AC system will blow warm air.

Regular cleaning and maintenance of the evaporator coils will prevent this problem. It will keep your air conditioning system running properly, and provide your home with the cool air you need.

Issues with the Outdoor Unit

Outdoor unit problems are another reason your air conditioner may be blowing hot air.

The outdoor condenser unit has important components like the condenser coil and the fan motor that are responsible for cooling the air. If the condenser coil is dirty, or the fan motor stops working, it can’t release heat properly and your AC won’t blow cold air.

Regularly cleaning the outdoor unit and checking for any damage or blockages, like debris around the fan, will cool your home as it should and keep your air conditioning unit running smoothly.

Outdoor unit of an LG inverter air conditioner

Electrical Problems: Blown Fuses and Tripped Circuit Breakers

Electrical problems like a blown fuse or a tripped circuit breaker can also make your air conditioner blow hot air.

If the circuit breaker connected to your AC unit trips, or a fuse blows, the outdoor unit will lose power and stop cooling the air. While the indoor unit will still run, the lack of cooling from the outside unit will ensure your AC is blowing warm air throughout your home.

If this happens, check your electrical switchboard to see if you have a tripped circuit breaker. Resetting it may solve the problem. If it persists though, call a professional aircon technician to inspect your system.

Why Call a Licensed Air Conditioning Technician

When your air conditioner is blowing warm air, you may be tempted to try DIY fixes. However, these can sometimes make the problem worse. Here’s why you need to hire a licensed air conditioning technician for a thorough service of your system:

  • Expertise: Licensed technicians have the training and experience to diagnose and fix complex problems like refrigerant leaks or faulty components that the average homeowner will miss.
  • Safety: Working with electrical systems, refrigerants and high-pressure components is dangerous. A professional technician will have the necessary licensing and experience to do the repairs safely.
  • Proper equipment: Technicians have the right tools and equipment to handle problems like dirty evaporator coils or malfunctioning outdoor units.
  • Warranty protection: Hiring a professional will keep your manufacturer’s warranty valid and prevent costly repairs later.

By calling a licensed HVAC technician, you’ll get your system repaired safely, efficiently and in compliance with regulations.

Get Your Broken AC Blowing Cold Fresh Air Again

If you find yourself asking “Why is my air conditioner blowing hot air?”, it’s usually a sign of an underlying issue that needs attention.

From incorrect thermostat settings to clogged air filters, refrigerant leaks or outdoor unit problems, there can be any number of possible causes behind your cooling system problems. Regular maintenance and quick troubleshooting can often fix these issues before they become bigger problems. If your air conditioning system still isn’t cooling properly don’t hesitate to call a professional HVAC technician to help.

With proper care and attention, your AC will be blowing cold air in no time and cool your home all summer.

Please note: Thanks for reading our blog “Why is My Air Conditioner Blowing Hot Air?”. This information is provided for advice purposes only. Regulations differ from state to state, so please consult your local authorities or an industry professional before proceeding with any work. See our Terms & Conditions here.

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