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Why Is My AC Blowing Warm Air? Troubleshooting Guide
Knowing what to do if your AC is blowing hot air can be overwhelming, even though it is a common issue with many possible causes. Understanding what might be causing your AC to blow warm air can help you take quick action and determine when it's time to call a professional.
Continue reading to learn why your air conditioner is blowing hot air and how the team at Home Comfort Experts can help.
Common Reasons for Warm Air Coming from Your Air Conditioner
It is never fun to experience warm air coming from your air conditioner, especially in the heat of the summer. Let’s first take a look at some common reasons why this would even happen in the first place.
- Dirty filter: A dirty air filter limits airflow and strains your AC unit, potentially causing it to blow warm air.
- Clogged/dirty outside AC unit: Your AC comprises two units, one indoor and one outdoor. If either one is strained or clogged up, it becomes difficult to supply cool air throughout the summer. Make sure your outdoor AC unit is free from dirt and debris.
- Thermostat issues: Certain settings on your thermostat may be set to supply your home with warm air, rather than cool air, even in the summertime.
- Refrigerant leak: Refrigerant is the fluid used to transform warm air into cool air. Even minimal leaks of refrigerant can cause a significant difference in the temperature of the air you receive, providing either warm or cool air.
- Frozen evaporator coils: Similar to refrigerant, evaporator coils are responsible for cooling your home. It’s counterintuitive, but if the evaporator coils freeze over, then your AC will blow warm air.
Start With the Basics: Quick Fixes You Can Try
How can you fix your AC blowing warm air? It’s always good to start with the basics to slowly ease your stress while thoroughly assessing the situation.
Start by checking simple things before assuming a significant breakdown:
Is the Thermostat Set Correctly?
Check your thermostat to ensure your AC is set to the correct settings. Sometimes, thermostats can be set to blow warm air instead of cool air.
Another possibility is that a power issue may cause the outside unit to lose power while the blower continues to run, resulting in warm air.
Is the Air Filter Dirty or Blocked?
See if you have a dirty or blocked air filter. If so, then it's time to replace it with a new one.
Airflow problems, such as a dirty or blocked air filter, can put strain on your AC unit and result in warm air or reduced cooling efficiency.
Mechanical or Electrical Issues That May Be the Cause
After you've assessed more common and simple possibilities for your AC blowing hot air, you’ll notice if the issue has been resolved or is persisting.
If your AC is still blowing warm air, it could signify mechanical or electrical failures. More significant issues like this will require professional inspection by an AC expert.
Refrigerant Leak or Low Refrigerant Levels
The refrigerant in an AC unit is necessary to provide cool air and transfer heat. AC units are sensitive to refrigerant problems, so it is important to check for leaks or low refrigerant levels.
Even seemingly small leaks or slightly low refrigerant levels can result in significant changes, such as inadequate cooling. Look out for these signs to see if you are experiencing a refrigerant leak or low refrigerant levels.
- Ice buildup
- Hissing sounds
- Poor airflow
There is a simple and quick test to determine if you may have refrigerant leaks.
- Turn off your AC
- Pour a soap solution (soap and water) into a spray bottle.
- Clean the refrigerant pipe area using a dry cloth, and make sure there is no wind.
- Spray the solution over the refrigerant pipe and watch for soap bubbles.
If there are no soap bubbles, then your AC unit most likely has a refrigerant leak. Contact a trusted, local professional HVAC technician from Home Comfort Experts to help restore your refrigerant levels.
Compressor Trouble
The AC compressor is responsible for transferring heat out of your home and is a necessary part of the cooling process. If you are experiencing AC compressor trouble, it can prevent your AC from cooling properly. The best way to tell if your AC compressor is failing is if you notice it making any rattling, clicking, or rumbling noises.
Faulty Capacitor or Contactor
Your AC unit operates with an electrical component known as a capacitor or contactor. If this part fails or becomes faulty, then the outdoor unit will have trouble starting or not start at all. You’ll have to check the outside AC unit to make sure.
Frozen Evaporator Coils
We know it sounds contradictory to think that your AC’s evaporator coils might be frozen in the heat of summer. However, this does indeed happen. When your AC has airflow problems, system damage, or even low refrigerant, the evaporator coils can become frozen, resulting in warm air.
How Your AC System’s Age Affects Performance
It’s important to keep in mind that one core issue for your AC system’s failure to blow cool air could be its age. If you have an AC system over 10–15 years old, it may struggle with performance, like properly cooling, or even with regular maintenance.
When to Call a Professional HVAC Technician
Now that you have done checks and assessments yourself, it should be pretty clear what the cause, or causes, are for your AC blowing warm air. With this information, it is best to call a professional for a full diagnosis.
Don’t think you can just solve the entire issue on your own. Tampering with an AC unit means potentially affecting your home’s HVAC system. Especially if you are experiencing issues with refrigerant, electrical, or compressor problems, call a professional HVAC technician.
Preventing the Problem: Tips to Keep Your AC Running Cold
Hiring a professional AC repair service can be expensive and challenging to schedule around your free time. Fortunately, there are actionable steps you can take to prevent problems and keep your air conditioner running efficiently.
- Change your air filter(s) regularly
- Schedule annual air conditioner tune-ups
- Keep the outdoor AC unit clean and clear of debris.
- Address early signs like unusual noises or weak airflow.
When to Call a Professional
It’s always best to hire a licensed and certified expert with experience to ensure everything runs perfectly.
Fortunately, homeowners can consult with Home Comfort Experts’ HVAC professionals when the problem is beyond fixing. We provide fast and efficient AC services to ensure our customers' complete satisfaction.
Need Fast Help With Your AC? Contact Home Comfort Experts
Home Comfort Experts handles all aspects of an air conditioning system, from selecting parts to full installation and complete replacement, to ensure your AC stays running at peak performance. Contact us today to schedule an appointment and get cool air flowing through your home again.
AC Blowing Warm Air FAQ
As discussed, AC blowing warm air can be caused by several issues. Many homeowners have frequent questions when trying to solve this for themselves or when getting professional help.
Should I turn off my AC if it’s blowing warm air?
Absolutely, yes. You should turn off your AC if it is blowing warm air. This can save you money and prevent further damage to a faulty air conditioner, especially if your evaporator coils are frozen.
If your evaporator or condenser coils are frozen, turn off your AC and let them melt. After about 24 hours, they should be completely thawed out and okay to turn on again.
Can I repair an AC that blows warm air myself?
While it is possible to fix an AC blowing warm air yourself, it is still best to call a certified AC professional. This is especially true if you have already done a system check yourself, identifying specific problems that only qualified experts can resolve.
Can ductwork problems make my AC blow warm air?
Ductwork problems can cause your AC to blow warm air, and they are a factor to consider when resolving your issue. Poor air circulation, air leaks, warm air infiltration, and restricted airflow are all possible ways that ductwork can cause warm air to flow into your home.
Consider installing one of our mini-split HVAC systems to eliminate the possibility of ductwork problems and the hassle of maintaining them. A mini-split HVAC system is a ductless type of air conditioning system that saves energy and costs.
Why does my AC blow warm air during the day but cool air at night?
Usually, your AC blowing warm air during the day and cool air at night is a sign that your AC unit is struggling against extreme heat temperatures during the day. Low refrigerant levels, clogged air filters, duct leaks, dirty condenser coils, and a faulty compressor can all contribute to this problem.
Who should I call if my AC isn’t cooling?
If your AC isn’t cooling, you should call a licensed and certified HVAC technician. Our professionals at Home Comfort Experts accurately assess and address the problem, restoring cool air into your home.
