AC Blowing Hot Air? Diagnose and Restore Cool Comfort | Blog

Picture a scorching summer day; you come home, fan in hand, expecting the relief of a cool house, only to be met with hot air blowing from your air conditioner. Many homeowners face this common yet frustrating predicament of a potential malfunction during the warm months.

Factors like incorrect thermostat settings, dirty air filters, or an absence of proper insulation to limit heat intake, or even significant issues like a damaged compressor can cause your AC to blow hot air, diminishing its cooling effectiveness. Other culprits can be low freon levels or issues with condensation on the coils.

This comprehensive guide with information gathered from expert AC technicians will help you understand why your AC might be blowing hot air, including possible causes and reliable troubleshooting solutions.

How Does an AC Work?

To understand why an air conditioner might be blowing hot air, we must first comprehend how an AC works. The primary role of an AC unit is to remove warm air from your home, cool it, and circulate it back. The fan at the heart of your unit is crucial for this cycle.

The air conditioning process begins with the indoor unit absorbing warm air from your home and passing it over the evaporator coils. These coils contain a refrigerant, often freon, that absorbs the present heat and transforms it from a low-pressure gas to a high-pressure liquid.

The compressor then pumps this high-pressure refrigerant into the condenser coils located in the outdoor unit. Here, the refrigerant releases the absorbed heat and cools down before returning it to the evaporator coils to continue the cycle. Any malfunction or inefficiency in this process can lead to ineffective cooling.

Regular AC maintenance in Las Vegas and other regions with extreme heat is vital to ensure efficient AC operation. In other words, a properly cleaned air filter and well-maintained coil and insulation are crucial elements of good AC health. Lack of maintenance could lead to problems such as condensation buildup and interruptions in freon flow, leading to your AC blowing hot air.

What Should the Air Temperature Coming Out of My Vents be?

The air temperature blowing out of your vents should ideally be 15-20 degrees cooler than the air entering the AC. You can measure this by using a standard thermometer, which is part of the technician’s toolkit.

To measure this, you need a standard thermometer. Here’s a step-by-step guide on how to do this.

Step 1: Measure the temperature of the air entering the return vent. This is the temperature of the air your AC unit is drawing in.

Step 2: Next, measure the temperature of the air coming out of the supply vent. This is the cooled air your AC is circulating back into your home.

Step 3: Subtract the supply vent temperature from the return vent temperature.

If the difference is less than 15 degrees, or your AC blows warm air, your AC system needs a solution to improve its cooling effectiveness. Several issues could cause this problem, including low refrigerant levels, dirty filters, a malfunctioning fan, or a compressor that’s not working as it should.

Reasons Why My AC Is Blowing Hot Air

One of the most common complaints among homeowners during the warm months is “My AC is blowing hot air.” This predicament can be frustrating, especially when you need cool relief. Let’s dive into why your AC unit might be blowing hot air and introduce effective troubles hooting techniques.

Incorrect Thermostat Settings

This may seem trivial, but it is worth checking your thermostat settings. There might be instances when your thermostat is inadvertently set to ‘heat’ instead of ‘cool.’ Moreover, a ‘fan only’ setting could also result in your AC blowing hot air as it circulates the warm indoor air without cooling it. Always ensure the thermostat is set correctly to avoid such a scenario.

Dirty or Clogged Air Filters

Clogged or dirty air filters can be a significant reason your air conditioning blows warm air. As air filters play an essential role in air purification in Las Vegas and other dusty areas, a clean air filter ensures that your AC system works efficiently. When filters become clogged, airflow is restricted, causing the system to overheat, coil condensation, and the evaporator coils to freeze.

Consequently, you might experience your AC blowing warm air. Regular filter changes are necessary to prevent this issue and maintain optimal cooling. Remember, a timely solution could save further expense.

Dirty Evaporator Coils

Like air filters, dirty evaporator coils can also lead to a situation where your AC blows hot air. When these coils, responsible for absorbing heat from the air, are covered in dirt and grime, they cannot effectively perform their function. This, in turn, means the warm air isn’t being cooled as it should be.

A thorough coil cleanup is an effective solution in this case. Regular cleaning of parts like the evaporator coil, crucial in your HVAC system, is paramount to maintain the unit’s efficiency. These coils are responsible for transferring heat and moisture from the air into water, improving your heating and cooling capacity.

Outdoor Unit Lost Power

At times, the outdoor unit might lose power due to issues with the circuit breaker, a blown fuse or a tripped breaker, while the indoor unit continues to run. As a result, the AC blows warm air because the system cannot complete the heating or cooling process without the outdoor unit. It’s recommended to check the outdoor unit’s power supply if you notice hot air blowing from your air conditioners – pay particular attention to the number on the breaker.

Refrigerant Leak

Refrigerant is a critical element in your air conditioning system. Just like the evaporator coil, it absorbs the heat from your home’s air and releases it outside. Therefore, a refrigerant leak can significantly affect the system’s cooling capacity, resulting in your AC blowing hot air.

Refrigerant leaks also release moisture into your HVAC system, leading to potential water damage. Besides, these leaks can cause harm to the environment and pose health risks. If you suspect a refrigerant leak, you must call an HVAC technician immediately to fix it.

Damaged Compressor

The compressor, akin to the heart of the air conditioning system, circulates the refrigerant between the indoor and outdoor air conditioners, working in conjunction with parts like the evaporator coil. If the compressor is damaged, the refrigerant cannot move, leading to your AC blowing warm air. This complex issue requires a professional HVAC technician’s expertise to identify and repair.

Air Duct Leaks

Finally, if you are experiencing hot air blowing from your air conditioner, it could be due to leaks in your ductwork. These leaks can cause the cooled air to escape before reaching your rooms, and warm outdoor air may enter the ducts, mixing with the cooled air. This problem typically calls for ductwork replacement or repair to seal the leaks. To prevent excess moisture from entering the system, it’s best that licensed HVAC technician conduct these repairs.

How to Fix AC Blowing Hot Air?

When you discover hot air blowing from your air conditioner, addressing the issue promptly is crucial. Here are step-by-step instructions on how to handle the situation:

Check the Thermostat

Ensure that your thermostat is set to ‘cool’ mode, not ‘heat’ or ‘fan only.’ The ‘fan only’ mode will circulate the indoor air without cooling it, which might give the feeling of your AC blowing hot air.

Replace or Clean the Air Filters

Clogged or dirty air filters restrict the airflow over the evaporator coils, causing them to freeze and blow your AC warm air. Regularly cleaning or replacing the air filters can resolve this issue.

Inspect the Outdoor Unit

Ensure the outdoor unit is running and check for any visible blockages like debris or dirt around it. If the unit is not working, it could be due to a tripped circuit breaker or a blown fuse.

Call a Professional

If you’ve checked all these factors and your air conditioners are still blowing warm air, it’s time to call in a professional HVAC technician. More complicated issues, such as a refrigerant leak or a damaged compressor, may require professional attention.

Consider Replacing Your AC

If your HVAC system is old and you’re repeatedly facing issues, it might be more cost-effective to consider AC replacements in Las Vegas or your local area. New HVAC systems, particularly air conditioners, are more energy-efficient and could save you money in the long run.

Regular maintenance is the key to preventing issues like your AC blowing hot air. Addressing minor issues as they arise can help avoid more significant problems, ensuring a comfortable and cool environment in your home.

There are several reasons why your AC might be blowing hot air, ranging from simple issues like incorrect thermostat settings to complex problems such as a damaged compressor or a leaky evaporator coil. Regular maintenance and immediate attention to problems ensure that each part of your HVAC system, down to the number on the circuit breaker, keeps you cool when needed.