10 Common Air Conditioner Problems and How to Fix Them
AC problems
When the summer heat hits, the last thing you want is an air conditioner that’s not working properly. Unfortunately, even the best systems can run into trouble without regular maintenance. Knowing the most common air conditioner problems and how to troubleshoot them can save you from discomfort, high energy bills, and expensive repairs.
Here’s a breakdown of the top 10 AC issues homeowners face, what causes them, and how you can fix or prevent them.
1. AC Not Cooling the House Properly
Problem:
Your air conditioner is running but not effectively cooling the room or home.
Causes:
- Clogged air filter
- Low refrigerant
- Dirty evaporator or condenser coils
- Thermostat malfunction
Fix:
- Replace or clean the air filter
- Check thermostat settings and batteries
- Call an HVAC technician to inspect refrigerant levels and clean coils
2. Air Conditioner Won’t Turn On
Problem:
The AC doesn’t start when you adjust the thermostat.
Causes:
- Tripped circuit breaker
- Blown fuse
- Faulty thermostat
- Wiring issues
Fix:
- Check and reset the circuit breaker
- Replace thermostat batteries
- Inspect wiring if accessible (or call a pro)
3. AC Blowing Warm Air
Problem:
Instead of cool air, your AC is pushing warm or room-temperature air.
Causes:
- Refrigerant leak
- Frozen evaporator coils
- Dirty condenser unit
- Reversing valve failure (heat pump systems)
Fix:
- Turn off the system to allow coils to thaw
- Schedule a refrigerant recharge and leak inspection
- Clean the outdoor unit to restore airflow
4. Strange Noises from the Unit
Problem:
Your AC is making banging, rattling, buzzing, or squealing sounds.
Causes:
- Loose components
- Debris in the fan
- Worn bearings or motor issues
- Failing compressor
Fix:
- Turn off the unit to prevent damage
- Clear any visible debris
- Call a technician for part replacement or diagnosis
5. Water Leaking from the AC
Problem:
You see water pooling around the air handler or dripping inside the home.
Causes:
- Clogged condensate drain line
- Cracked drain pan
- Frozen coils melting too fast
Fix:
- Flush the condensate line with vinegar or a wet/dry vacuum
- Replace the drain pan if cracked
- Address frozen coil causes (low refrigerant, airflow blockage)
6. AC Cycling On and Off Frequently
Problem:
The unit turns on and off too quickly, a condition called short cycling.
Causes:
- Oversized AC unit
- Clogged filters
- Refrigerant issues
- Faulty thermostat
Fix:
- Clean or replace filters
- Ensure the thermostat is properly placed (away from heat sources)
- If frequent, consult an HVAC pro to size your system correctly
7. Foul Smells Coming from Vents
Problem:
Musty, burning, or rotten smells when the AC is running.
Causes:
- Mold/mildew in the system
- Burned-out wire insulation
- Dead rodents in ductwork
Fix:
- Clean evaporator coils and drain lines
- Schedule duct cleaning
- Replace any damaged electrical components
8. Frozen Evaporator Coils
Problem:
The AC stops working or blows warm air, and you notice ice buildup.
Causes:
- Restricted airflow
- Dirty coils
- Low refrigerant
- Continuous operation in low temperatures
Fix:
- Turn off the system and allow coils to thaw
- Clean air filters and coils
- Call a technician to check refrigerant levels
9. Uneven Cooling in Rooms
Problem:
Some rooms are freezing, others are still warm.
Causes:
- Blocked or closed vents
- Poor insulation
- Ductwork leaks
- Thermostat location or zoning issues
Fix:
- Make sure all vents are open and unobstructed
- Consider zoned HVAC systems or duct sealing
- Add insulation to problem areas
10. High Energy Bills
Problem:
Your utility bills spike even though your usage hasn’t changed.
Causes:
- Dirty filters and coils
- Old or inefficient AC unit
- Refrigerant or duct leaks
- Poor insulation or open windows
Fix:
- Perform seasonal maintenance and tune-ups
- Upgrade to a high-SEER, energy-efficient model
- Seal leaks and improve home insulation
🔧 Pro Tips to Avoid AC Problems
- Change filters every 1–3 months
- Schedule professional AC maintenance every spring
- Keep the area around your outdoor unit clear
- Install a smart thermostat for better temperature control
- Clean your ductwork every few years
When to Call the Pros
While some AC problems are simple DIY fixes, issues like refrigerant leaks, electrical problems, or compressor failure require certified HVAC professionals. Ignoring these problems can lead to costly breakdowns or complete system failure.
If your AC is over 12–15 years old and requires frequent repairs, it may be more cost-effective to consider a replacement.
Conclusion
Understanding these common air conditioner problems and how to fix them can help you maintain your system, improve home comfort, and avoid emergency breakdowns. Regular maintenance and knowing when to call a pro are key to keeping your AC running smoothly all summer long.
Need help with any of the issues above? Contact All Week Plumbing & HVAC—New Jersey’s trusted AC repair and installation experts.
