A/C Not Blowing Cold Air: Common Reasons and Solutions

30 мая, 2024

Air conditioning is essential for keeping our homes comfortable, especially during hot summer days. 

We all love comfort, and when the A/C is not blowing cold air and not cooling the house, life becomes a little bit harder: broken A/C definitely affects your productivity and well-being. The cooling of indoor air is crucial in warm climates where maintaining a comfortable temperature during the summer is a must-have.

Understanding the common reasons behind this issue and how to troubleshoot them can save you time, money, nerves, and discomfort. Let’s delve into the intricacies of A/C units and explore practical solutions to restore their cooling efficiency.

Understanding Your A/C

The cooling process of your air conditioner lies in the circulation of the refrigerant. Refrigerant, the blood of the air conditioner, circulates between indoor (evaporator coil) and outdoor (condenser unit) components of the A/C. Another significant feature about refrigerant: it is capable of changing its state from liquid to gas and back again rapidly. 

Here’s how it works: To understand the cooling process we need to cover the main components of the air conditioner, illustrated in the diagram below. You may also watch this interactive video to see the air conditioning work in action

The cooling process in AC, A/C cooling process, Structure of AC

A. EVAPORATOR COIL. The evaporator coil is located inside the house and absorbs heat and humidity from indoor air to cool it down.

B. BLOWER MOTOR. The blower motor circulates air throughout the building. It is responsible for supplying the air to the evaporator coil, which cools the air before it is returned to the living space.

C. CONDENSER COILS. The condenser coil is another crucial part of an air conditioner that helps to transform the hot vapor refrigerant into medium temperature, high-pressure liquid with the help of the condenser fan motor.

D. COMPRESSOR. When you turn on your A/C with the thermostat, the cooling process starts with the compressor. Located inside the outdoor unit, the compressor pumps the cold gaseous refrigerant coming from the indoor evaporator coil, turning it into a hot, high-pressure gas and sending it to the condenser coil.

E. CONDENSER FAN. Located on the top of the outdoor unit (condenser unit), the condenser fan speeds up the cooling of the refrigerant. Once the refrigerant is cooled down, it goes to the indoor evaporator coil.

F. AIR FILTER. Keeps the air clean and free of contaminants. It works by capturing dust, debris, bacteria, allergens, and other pollutants as air passes through it.

G. TXV VALVE. The TXV valve, also known as expansion valve or pressure dropper, is a small device that drops the pressure from the refrigerant before it enters the evaporator coil. This process makes the refrigerant a low-temperature, low-pressure liquid.

Common Reasons for A/C Not Blowing Cold Air

Now, when you know how your A/C unit functions, you can indicate possible reasons why it might not work properly. Several factors can contribute to your A/C unit failing to produce cold air:

  1. Dirty Air Filter: Go and check your air filter if it has dust, dirt or anything that restricts airflow. A clogged or dirty air filter can restrict airflow, making it harder for your A/C to cool the air efficiently.
  2. Refrigerant Leak: Look around your A/C, if it has any leaking around, then most probably your refrigerant is leaking. Low refrigerant levels due to a leak can hinder the A/C’s ability to cool the air effectively.
  3. Faulty Thermostat: If you see unusual numbers on your thermostat that might be a reason. A malfunctioning thermostat can lead to incorrect temperature readings, affecting the A/C’s cooling performance.
  4. Dirty Condenser Coils: Again the question of cleanliness! A buildup of dust and debris on the condenser coils can reduce heat transfer, decreasing the cooling capacity of the A/C.
  5. Blocked Air Vents: If there is anything resisting your A/C’s vents, that might be the case as well. Blocked or closed air vents can restrict airflow, leading to reduced cooling in specific areas or rooms.
  6. Faulty Compressor: When an air conditioner’s compressor is in its final stages of operation, you may experience loud noises, warm air, airflow difficulties, uneven cooling, and electrical malfunctions. Issues with the compressor can prevent the A/C from properly cooling the air, requiring professional attention.
  7. Electrical Issues: Watch out for electrical joints, they can be a problem too. Problems with electrical components such as capacitors or relays can impact the A/C’s cooling efficiency.
  8. Old or Inefficient Unit: An older or improperly sized A/C unit may struggle to cool effectively, potentially indicating the need for an upgrade or maintenance.

Understanding how these issues impact your A/C’s performance is essential for troubleshooting effectively.

DIY Solutions and Troubleshooting

If your A/C is not blowing cold air, here are some steps you can take. Remember to be careful and pay attention to safety.

  1. Dirty Air Filter
    Check and replace the air filter regularly, typically every 1-3 months, or as the manufacturer recommends.
  2. Refrigerant Leak
    If you suspect a refrigerant leak (e.g., if your A/C isn’t cooling properly), contact a professional HVAC technician to inspect and repair the leak and recharge the refrigerant if necessary. Call us and we will help you out!
  3. Faulty Thermostat
    Check the thermostat settings and ensure they are correctly set to your desired temperature. If the thermostat is malfunctioning (e.g., displaying incorrect readings), consider replacing it with a new one.
  4. Dirty Condenser Coils
    Clean the condenser coils regularly, typically once a year, to remove dust and debris. Use a gentle brush or vacuum cleaner to avoid damaging the coils.
  5. Blocked Air Vents
    Ensure all air vents are open and unobstructed by furniture, curtains, or other objects. This allows for proper airflow and cooling throughout your home.
  6. Faulty Compressor
    If you suspect issues with the compressor (e.g., unusual noises, inconsistent cooling), contact a professional HVAC technician to diagnose and repair the problem.
  7. Electrical Issues
    If you experience electrical issues (e.g., A/C not turning on, frequent circuit breaker trips), contact an electrician or HVAC technician to inspect and repair any electrical components or wiring problems.
  8. Old or Inefficient Unit
    Consider upgrading to a newer, more energy-efficient model. Regular maintenance and tune-ups can also improve the performance of older units.

Knowing when to attempt DIY fixes and when to seek professional help is crucial to avoid further damage to your A/C unit. 

When to Call a Professional

However, there are situations when it is better to call a professional and not intervene by yourself. Examples of such issues are: 

  1. Inadequate Cooling: When your A/C fails to cool your home effectively, blowing warm air instead of cold, it’s a clear indicator of underlying issues like refrigerant leaks or compressor problems. These issues require professional diagnosis and repair to restore optimal cooling performance.
  2. Unusual Noises: Strange sounds emanating from your AC unit, such as grinding, banging, or squealing noises, often indicate mechanical issues that require immediate attention from a trained technician. Ignoring these noises can lead to more significant and costly repairs down the line.
  3. Weak Airflow or Uneven Cooling: If you notice weak airflow from your vents or inconsistencies in cooling throughout different rooms in your home, it could signify problems like clogged air filters, ductwork issues, or a malfunctioning blower motor. A professional technician can identify and resolve these airflow issues effectively.
  4. Frequent Cycling: Short cycling, where your A/C unit turns on and off frequently in short intervals, can indicate problems like an oversized unit, faulty thermostat, or compressor issues. These issues not only reduce energy efficiency but can also cause premature wear and tear on your A/C system if left unaddressed.
  5. Water Leaks: Any signs of water leaks or moisture accumulation around your A/C unit or indoor air handler should prompt immediate attention from a professional technician. These leaks can result from drainage issues, refrigerant leaks, or condensate pump malfunctions, all requiring professional repair to prevent further damage.
  6. Increased Energy Bills: A sudden spike in your energy bills without a corresponding increase in A/C usage could indicate inefficiencies or malfunctions in your cooling system. A professional technician can conduct a thorough inspection to identify and address the root cause of increased energy consumption.
  7. Strange Odors: Musty, moldy, or burning odors coming from your vents are warning signs of potential mold growth, electrical problems, or overheating components within your A/C system. A professional should investigate and resolve these issues promptly to ensure indoor air quality and safety.
  8. Thermostat Problems: Malfunctioning thermostats that fail to respond accurately or display incorrect temperatures can lead to inconsistent cooling and comfort issues. A professional technician can recalibrate or replace the thermostat as needed to ensure precise temperature control and efficient operation of your A/C system.

Expect thorough diagnostics, expert repairs, and reliable service when hiring professional A/C technicians. And our company will happily help you to fix any of these issues.

Preventative Maintenance

You can avoid repairing your A/C or calling for professionals with the regular maintenance. To prevent A/C issues, consider these tips:

  1. Regularly Clean and Replace Filters: It depends on your living area and the climate there. Usually, aim to clean or replace filters at least twice a year, before heating or cooling seasons.
  2. Schedule Professional Tune-Ups: Schedule annual maintenance with a certified technician to ensure optimal performance.
  3. Clear Surrounding Debris: Keep the area around the outdoor unit clear of debris and vegetation to promote airflow.

Routine maintenance plays a vital role in prolonging your A/C’s lifespan and preventing unexpected breakdowns, saving energy bills. IRBIS HVAC is always there to help you! Just contact us.


Overall, understanding why your A/C is not blowing cold air empowers you to take proactive measures and ensure optimal cooling performance. Regular maintenance, timely repairs, and knowing when to seek professional assistance are key to keeping your A/C unit running efficiently and maintaining indoor comfort throughout the year.


Why is my air conditioner not blowing cold air?

If your air conditioner isn’t blowing cold air, it could be due to a dirty air filter, low refrigerant levels, frozen evaporator coils, thermostat issues, or a blockage in the condenser unit. Check and replace the filter if necessary, ensure the thermostat is set correctly, and inspect the outdoor unit for debris. If these steps don’t resolve the issue, consider contacting a professional to check for refrigerant leaks or other mechanical problems.

How often should I replace or clean my A/C filters?

You should check your A/C filter every month, and if it gets dirty replace it. The environment you live in influences the state of your filter a lot, so usually once in 90 days or three months should be enough.

Can extreme outdoor temperatures affect my A/C’s cooling efficiency?

Yes, it can. When the outdoor temperature is high your A/C unit works harder and some of its parts get overworked. As a result, you will need to repair your unit’s parts more often, or replace the A/C.

Are there any smart thermostats that can help diagnose A/C issues?

Yes, there are. Smart thermostats help you not only control your cooling system from remote but also might be an indicator when your A/C has issues. The warning will show up on the screen of your thermostat or you will receive a notification to your smartphone if they are connected.

How do I know if my A/C needs more refrigerant?

There are several symptoms you might challenge when your A/C is low on refrigerant.

  1. It takes longer to cool your house during the daytime but faster in the evenings.
  2. You receive higher bills even if the workload of your A/C seems the same.
  3. You hear unusual noises from your A/C.

In case your A/C matches with one or several symptoms, probably, it is better to change your refrigerant.

Can landscaping around my outdoor unit affect its performance?

Landscaping that blocks the airflow around your air conditioning unit can cause problems. When plants, fences, or debris restrict the airflow through the coils, the unit can’t effectively release the heat it generates. This makes the A/C work harder, uses more energy, and can even lead to damage if loose materials get into the unit.

How can I improve the efficiency of my air conditioner?

Improving the efficiency of your air conditioner can be achieved by ensuring regular maintenance checks, sealing leaks in windows and doors, using window coverings to reduce heat gain, and setting your thermostat to a comfortable yet economical temperature. Additionally, upgrading to a high-efficiency A/C unit or using fans to assist in even air distribution can also enhance efficiency.

Can I run my A/C without a filter temporarily?

Running your A/C without a filter is not recommended even temporarily, as it allows dirt and debris to enter the unit, which can clog the internal mechanisms and reduce efficiency. This can lead to increased wear and tear, potentially resulting in costly repairs or premature failure of the system.

How does direct sunlight exposure affect my indoor cooling unit’s performance?

Direct sunlight on your indoor cooling unit can increase its operational temperature, making it work harder to cool the air. This reduces efficiency and can lead to higher electricity costs. Using blinds, curtains, or relocating the unit to a less exposed area can help mitigate this effect.

What should I do if my A/C emits a foul odor when it runs?

If your air conditioner emits a foul or musty odor when running, this might be due to mold or mildew growth within the unit or the ductwork. Cleaning the evaporator coils and ensuring the drainage system is clear can often resolve this issue. However, if the smell persists, it’s advisable to consult a professional to inspect and clean the ductwork and other components.

What is the role of the capacitor in my A/C unit, and how do I know if it’s failing?

The capacitor in your A/C unit helps start the compressor and the condenser fan motor. If your A/C is having trouble starting, hums without turning on, or turns off shortly after starting, these could be signs that the capacitor is failing. Testing the capacitor involves using a multimeter, and if it shows a lower capacitance than the rated value, it needs to be replaced.