Air conditioners keep homes comfortable, especially during peak summer months. According to the U.S. Energy Administration, nearly 90% of households use air conditioning units.
But after sitting idle during the off-season, AC units often develop issues. Some problems are minor and easy to fix. Others can lead to costly repairs if ignored.
This guide helps homeowners recognize and address common air conditioning problems before they escalate.
Bad Capacitor
The capacitor gives the AC motor the push it needs to start. Heat exposure, voltage fluctuations, and aging wear capacitors down. A failing capacitor can prevent the AC from turning on or cause frequent shutdowns.
Solutions:
- Replace failing capacitors.
- Use the correct capacitor size to extend lifespan.
AC Refrigerant Leak
Refrigerant absorbs heat and helps cool the air. Leaks reduce efficiency and pose environmental and health risks. Pinhole leaks in refrigerant lines or improper refrigerant levels (overcharging or undercharging) are common causes.
Solutions:
- Listen for hissing sounds or check for warm air from vents.
- Call a professional to repair leaks and recharge refrigerant.
Indoor Water Leaks
Water leaks inside the house signals a clogged condensate drain line or a broken condensate pump.
Solutions:
- Use a vacuum or vinegar to clear the drain line.
- Call a professional if the pump malfunctions.
Outdoor Water Leaks
If water pools near the outdoor unit, a clogged air filter, a cracked condensate pan, or a faulty AC seal could be the cause.
Solution:
- Turn off the unit, disconnect power, and call a professional.
Frozen Evaporator Coil
A frozen evaporator coil usually points to low refrigerant, temperatures below 62ºF, or airflow restrictions from clogged filters.
Solutions:
- Check refrigerant levels.
- Avoid running the AC in low temperatures.
- Inspect and clean components regularly.
Dirty Air Filter
A clogged filter blocks airflow, reducing efficiency and increasing strain on the system.
Solution:
- Replace or clean filters every 1-3 months during peak season.
Damaged or Malfunctioning Compressor
The compressor circulates refrigerant through the system. A blown fuse, a tripped breaker, or faulty valves can cause failure.
Solutions:
- Check for tripped breakers and replace fuses.
- Have an HVAC professional diagnose the issue.
Thermostat Sensor Problems
A misaligned or broken thermostat sensor can throw off temperature readings, making the system cycle incorrectly.
Solutions:
- Adjust the sensor so it’s near but not touching the coil.
- Check thermostat settings and recalibrate if needed.
Thermostat Issues
A faulty thermostat can cause short cycling, inconsistent temperatures, or failure to turn on.
Solutions:
- Replace dead batteries or check the breaker.
- Level the thermostat and clean internal components.
- Adjust anticipator settings.
- Upgrade to a smart thermostat for better control.
AC Making Noises
Grinding, clicking, or bubbling sounds indicate serious issues, such as compressor failure, a blocked fan, or a refrigerant leak.
Solution:
- Don’t ignore noises—call a professional immediately.
AC Smells Bad
Mold, electrical burning, or gas smells suggest a problem.
Solutions:
- Clean the unit if it’s a seasonal smell.
- Call a professional for electrical or gas-related odors.
Circuit Breaker Keeps Tripping
Power surges, capacitor failure, dirty filters, or compressor failure can overload the circuit.
Solution:
- Turn off the unit, do not reset the breaker, and call a professional.
Leaking Ducts
Leaky ducts waste energy and reduce efficiency.
Solutions:
- Inspect ducts and seal holes with mastic air duct sealant.
- Call a professional for a full inspection.
Outside Fan Not Functioning
The fan expels heat from the system. If it stops, the AC won’t cool properly. Causes include a bad fan motor, power supply issues, or a defective compressor contactor.
Solutions:
- Manually start the fan as a temporary fix.
- Reset the circuit breaker if tripped.
- Call an AC electrician for capacitor or motor replacement.
Weak Airflow
Blocked vents, clogged filters, or a faulty blower motor can cause poor airflow.
Solutions:
- Clean filters.
- Recalibrate the thermostat.
- Clear vent blockages.
AC Won’t Turn Off
A malfunctioning fan relay or incorrect refrigerant levels can cause the system to keep running.
Solutions:
- Set the thermostat fan to “off.”
- Inspect relay switches and refrigerant levels.
- Call a professional if necessary.
Mister Greenway Can Help Fix Common AC Problems
Addressing AC problems early prevents expensive repairs. Some issues have DIY fixes, but others require a trained HVAC technician.
Mister Greenway provides AC repair, maintenance, and installation for homeowners in Nashville, TN, and surrounding areas. We’ll send the cavalry to get your AC running smoothly again.
FAQs – Common AC Problems
Homeowners often have questions about AC issues. Here are answers to some of the most common ones:
What’s the difference between an air conditioner and a heat pump?
Air conditioners cool the air but can’t provide heat. Heat pumps work like an AC but also reverse the process to heat your home in winter.
How often should I change my AC filter?
Every 1-3 months, depending on usage and air quality.
Can I recharge my AC refrigerant myself?
No. Handling refrigerant requires professional certification. If you suspect a leak, call an HVAC technician.
Why is my AC making a hissing noise?
A hissing sound likely means a refrigerant leak. Turn off the unit and call a professional.
Final Thoughts
Regular maintenance prevents most AC issues. Schedule professional service at least once a year to keep your system efficient. If you notice any problems, don’t wait. Ensure your AC is in peak condition before summer arrives.
