When your AC is blowing warm air just as summer begins, it can be frustrating and uncomfortable. In some cases, the cause is simple and easy to fix. In others, it may point to a more serious issue. Use this guide to help you identify the problem and take the right steps before calling in a professional.
1. Check the Thermostat Settings
Start with the thermostat. It is one of the most common sources of cooling issues and also the easiest to correct.
Common things to check:
- The thermostat is set to “Heat” instead of “Cool”
- The fan is set to “On” instead of “Auto”
- The temperature setting is too high
- Batteries are dead or running low
- Programming or connection issues with smart thermostats
What to do:
Set the thermostat to “Cool” and adjust it to a temperature lower than the current room temperature. If you are using a smart thermostat, double-check the schedule and replace the batteries if needed.
2. Replace a Dirty Air Filter
A clogged air filter can block airflow, making it difficult for your system to cool the home properly.
Signs of a dirty filter include:
- Weak airflow from vents
- Dust buildup around the vents or rooms
- Higher energy bills than usual
What to do:
Replace the air filter every one to three months. A clean filter improves airflow and helps your system run more efficiently.
3. Low Refrigerant or a Leak
Your AC uses refrigerant to absorb heat from inside your home. If levels are low or there is a leak, the system may run continuously but only produce warm air.
Watch for these signs:
- Ice forming on the coils or refrigerant lines
- A hissing sound near the AC unit
- Higher utility bills without increased usage
- AC runs constantly but fails to cool
What to do:
Refrigerant issues should be handled by a licensed HVAC technician. Never attempt to fix a leak or recharge refrigerant on your own.
4. Dirty Outdoor Condenser Coils
The outdoor unit of your AC releases heat that it removes from your home. If the condenser coils are dirty or blocked by debris, heat cannot escape efficiently and your system may blow warm air.
Possible signs:
- AC is running but not cooling
- The outdoor unit feels very hot
- Cooling cycles last longer than normal
What to do:
Turn off the system and gently rinse the coils with a garden hose. Avoid using high pressure to prevent damage. For heavy dirt or buildup, professional cleaning is recommended.
5. Duct Leaks or Blockages
If there are holes or gaps in your ductwork, cool air can escape before it reaches your living spaces. This can reduce performance and cause your AC to blow warm air.
Look for the following signs:
- Uneven temperatures from room to room
- Loose, disconnected, or visibly damaged ducts
- Unexplained increases in energy bills
What to do:
Inspect accessible ducts for gaps and seal them using HVAC tape. For more serious duct issues, such as blockages or hidden leaks, it is best to schedule a professional inspection and cleaning.
6. Check the Breakers
Your air conditioning system has two circuit breakers; one for the indoor unit and one for the outdoor unit. If the breaker for the outdoor unit has tripped, the indoor fan may still blow air, but it will not be cool.
What to do:
Find your electrical panel and check both breakers. If one is tripped, reset it. If it trips again soon after, stop using the system and contact an HVAC technician. Repeated tripping could indicate an electrical issue that needs attention.
7. Compressor Failure
The compressor circulates refrigerant through the AC system. If it fails, the system may still turn on but will not cool your home.
Common signs of compressor trouble:
- AC turns on but does not produce cool air
- Frequent system shutoffs or restarts
- Breaker trips when the AC starts
- Unusual noises from the outdoor unit
What to do:
Compressor issues usually require professional repair. If your system is older, replacing the entire unit might be a more cost-effective solution.
Still Asking “Why Is My AC Blowing Warm Air?”
If your air conditioner still isn’t cooling properly, it’s time to call the experts at Knowledge HVAC & Refrigeration Ltd. Our certified technicians will quickly diagnose the problem and get your system back to peak performance. We offer fast, dependable repairs along with preventative maintenance to keep your home cool and comfortable all summer long.
Want to get your cool air flowing again?
Reach out to Knowledge HVAC & Refrigeration Ltd and let us help you stay comfortable.
