Why is My AC Blowing Warm Air?

There’s nothing worse than trying to relax inside on a hot, Summer day and finding out that your air conditioning unit is blowing warm air. With Maryland temperatures in the 90’s and humidity at it’s highest during the peak of summer, having your A/C unit working in tip-top condition is a necessity. 

It’s important to know the reasons why your air conditioner could be blowing warm air ahead of time so you aren’t stuck sweating this summer. Here are some factors that play into why your AC is blowing warm air, and our suggestions on how to avoid and fix them:

1. Low or Leaking Refrigerant

One of the most common causes for an AC blowing warm air is low refrigerant. A refrigerant is essential to maintain your unit’s best performance. It is the fluid that absorbs heat and humidity from the air. If your AC is not cooling, it may be because the refrigerant is leaking and whatever is left is not enough to effectively keep your home cool.

Unfortunately, fixing this is not as simple as replacing the refrigerant. While our HVAC technicians can add refrigerant, this is only a temporary fix and sometimes may only last a few days depending on how bad your leak is. Finding the leaks and repairing holes can be time consuming and expensive. If not promptly fixed, it may even cause damage to the compressor motor. Some of the tell-tale signs of a leaking refrigerant are hissing or bubbling noises and a buildup of ice on the outside unit.  In order to get this fixed properly, we need to locate and repair your leak.

2. Thermostat Settings

If you detect your AC blowing warm air, it may be due to problems with your thermostat settings. Be sure your system is set to “COOL,” your fan is switched to “AUTO,” and your temperature setting is below what the room temperature reads on your thermostat. 

Also, consider a programmable thermostat. Older control systems tend to malfunction easily. With a programmable one, you can keep the temperature inside your home consistent every time. Your energy savings will make the price of getting one worth it.

3. Dirty Air Filters

This is the most common reason why your air conditioner is not cooling properly. Clogged air filters can cause various problems in your unit. It can even interfere with how your thermostat works. If the filter is dirty and unclean due to dust, the passage of cool and warm air inside the ducts is blocked. This then leads to the evaporator coils freezing, resulting in your house AC blowing warm air. This is why replacing your air conditioner filters regularly is such an important aspect of maintenance.

An AC unit running on clean filters will operate smoothly for a longer time. It can also lower your energy costs. Clean or replace your dirty filters at least every three months or as needed.

4. Frozen Evaporator Coils

Another cause of your AC blowing warm air is frozen evaporator coils. Filled with refrigerant, these coils act like a sponge and soak up heat from the air. Without proper airflow, the evaporator gets too cold, resulting in ice buildup. When this happens, your unit will release warm air, or sometimes no air at all. It is important that warm air gets to circulate around the coils for them to work properly.

Dirty air filters lead to dirty and frozen evaporator coils. However, while filters are easy enough to replace by yourself, you need an HVAC technician to clean the coils. Do not attempt to remove them, as they can easily be damaged by improper handling.

5. Dirty Condenser Coils

Your air conditioner’s condenser coils are responsible for removing heat from the air and expelling it outside your house. As part of the outdoor unit, they are frequently exposed to the elements and over time, dirt and grime accumulate on the coils. This impedes heat transfer. You will start noticing this with your AC blowing warm air in the house. The dirty coils put undue strain on the entire unit, leading to increased wear and tear on parts.

Clean the outdoor unit regularly to give your condenser ample room to breathe. Remove weed and debris surrounding the unit and hose it down to remove caked-up dirt. Do not forget to shut off the power before cleaning.

6. Fan Problems

There are several reasons why the fans in your AC unit do not work properly. It could be because of a faulty motor, worn belts, or lack of lubrication. Dirt and debris can also cause problems in the fans. If the fan, either on the indoor or outdoor unit, fails to work as it should, this will facilitate poor airflow. This then leads to your AC blowing warm air instead of the cool ones you expect. If neglected, fan problems may result in compressor failure. This is a fix you need to call us at Pro-Tech HVAC Home for.

7. Clogged Drains

Another reason for an AC blowing warm air is clogged drains. The moisture that the AC removes from the air is supposed to be expelled through a drain line. If this line gets blocked due to debris or dirt, the water can go back and damage the AC’s system. In a worst-case scenario, the water leaks and goes through the walls and ceilings, as well as furnishings. This leads to mold growth if not discovered right away.

Some clogs are relatively easy for you to fix. If the blockage is visible when you look at the drainpipe, you can remove it manually wearing protective gloves or you can use a wet/dry vacuum to suction the blockage out. BUT, it is going to be really messy so if you don’t want to see all that gunk, better call Pro-Tech HVAC Home.

Almost all the causes of air conditioner problems can be prevented with preventative maintenance.

Aside from extending the lifespan of your AC system, it can reduce your energy bills by improving your unit’s energy efficiency. Contact us to ensure your preventative maintenance is completed every Spring, before it gets hot and you power up your AC for the first time. With this, you will never have to experience your AC blowing warm air in the house when Summer comes.

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Pro-Tech HVAC Home offers new installation, replacement, repairs and maintenance of heating and air conditioning systems in the Annapolis area. Our customers rely on us for honest and reliable service for air conditioners, heat pumps, gas furnaces, Mitsubishi systems, and more. We’re happy to answer questions, troubleshoot, and help you choose the best HVAC system for you and your family. We’re always happy to help answer your questions, so please give us a call or send us an email.