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7 Common Emergency AC Issues and How to Handle Them

Cassie Pound, owner of Quality Heating, Cooling, Plumbing & Electric
Published by
Cassie Pound
June 5, 2024
7 Common Emergency AC Issues and How to Handle Them

When your AC suddenly stops cooling or makes strange noises, it can be a frustrating experience, especially during sweltering days. You might wonder if it’s a minor issue you can tackle yourself or need professional help. Knowing how to handle common emergency AC issues, like water leaks or a malfunctioning thermostat, can save you time and money. But what steps should you take first? Understanding these problems and their solutions can make a significant difference in maintaining a comfortable home environment. Let’s examine practical ways to address these common AC issues efficiently.

Sudden Loss of Cooling

One common emergency AC issue is a sudden loss of cooling, which can leave you sweltering in high temperatures. Several factors, including a power outage or a refrigerant leak, can cause this problem. When your AC stops cooling, the first thing to check is whether there’s been a recent power outage. A power outage can disrupt the system’s function, and you might need to reset your circuit breaker. Turn off the AC before resetting the breaker to avoid potential electrical issues.

Another possible cause of cooling loss is a refrigerant leak. Refrigerant is crucial for your AC to cool the air; a leak can greatly reduce efficiency. If you suspect a refrigerant leak, look for signs like hissing sounds from the unit or ice buildup on the evaporator coils. It’s important not to attempt fixing a refrigerant leak yourself, as it requires specialized knowledge and equipment. Instead, contact a professional HVAC technician to diagnose and repair the issue safely.

AC Not Turning On

If your AC isn’t turning on, it can be just as frustrating as a sudden cooling loss. First, check the circuit breaker. Sometimes, a tripped breaker can be the culprit. Locate your electrical panel and find the breaker labeled for your AC. If it’s tripped, switch it off and then back on.

If the circuit breaker isn’t the issue, wiring problems might be the next thing to consider. Over time, wires can become loose or damaged, disrupting power flow to your AC unit. You must inspect the wiring connections at the thermostat and the AC unit. Ensure all connections are secure and free of corrosion. If you’re uncomfortable handling electrical components, contacting a professional is best.

Another potential cause could be a malfunctioning thermostat. Check if the display is working and set to the correct mode. Sometimes, simply replacing the batteries can fix the problem. If the thermostat still doesn’t respond, it might need recalibration or replacement.

Lastly, verify that the outdoor unit’s disconnect switch is on. This switch, usually near the outdoor unit, can sometimes be accidentally turned off. If all else fails, contact a professional technician.

Strange Noises

Hearing strange noises from your AC unit can be concerning and often indicate underlying issues that need immediate attention. One common cause of unusual sounds is loose components. Over time, screws and bolts can become loose because of the constant vibration and movement of the unit. If you hear rattling or clanking, it’s important to turn off the AC and inspect the unit. Tighten any visible screws or bolts to see if that resolves the issue.

Another frequent cause of strange noises is fan obstruction. When debris, such as leaves or twigs, gets inside the outdoor unit, it can obstruct the fan blades, causing them to hit the debris and create loud, unusual sounds. To handle this, first, turn off the AC to avoid any accidents. Then, carefully remove any visible debris from the fan area.

If neither loose components nor fan obstruction is the problem, the issue might be more complex, involving the motor or other internal parts. In such cases, it’s best to call a professional technician. Attempting to fix deeper mechanical problems without proper knowledge can lead to further damage or even void your warranty.

Unpleasant Odors

Detecting unpleasant odors from your AC unit can be alarming and uncomfortable, often signaling issues that need immediate attention. These odors can stem from various sources, and identifying the root cause is vital for maintaining your system’s efficiency and your home’s air quality.

One common cause of bad smells is dirty filters, which can trap dust and debris, leading to musty odors. Another frequent culprit is mold growth within the unit, usually because of moisture accumulation. When mold grows on the evaporator coils or within the ductwork, it releases a distinctive, musty scent.

Here’s how you can address these odors:

  • Replace dirty filters: Regularly changing AC filters can prevent dust buildup and improve air quality.
  • Clean the evaporator coils: Make sure that the coils are free from mold and debris.
  • Inspect ductwork for mold: Check for mold growth within the ducts and clean them if needed.
  • Run a dehumidifier: Reducing indoor humidity can help prevent mold growth.
  • Schedule professional maintenance: Have a technician inspect and clean your AC system regularly.

Water Leaks

Water leaks from your AC unit can quickly escalate into significant problems, damaging your home and reducing the system’s efficiency. It’s important to address these leaks promptly to avoid costly repairs.

First, check for a clogged drain. Your AC unit removes moisture from the air, which should exit through a drain line. If the drain gets clogged with dirt, algae, or debris, water has nowhere to go and starts leaking from the unit. You can unclog the drain by using a wet/dry vacuum to suck out the blockage or a long, flexible brush to clean the line. Regularly inspect and clean the drain to prevent this issue from recurring.

Next, examine the pipes for damage. Over time, pipes can develop cracks or become loose, leading to leaks. If you spot any pipe damage, you should tighten the connections or replace the damaged sections. If you’re unsure about handling pipe repairs yourself, it’s advisable to call a professional.

Additionally, make sure the unit is level. An uneven AC unit can cause water to pool and overflow. Use a level to check the alignment and adjust the unit’s position. By addressing these potential causes, you can effectively manage water leaks from your AC unit.

Frozen Evaporator Coil

A frozen evaporator coil is another common issue that can compromise your AC’s efficiency. This problem can arise from restricted airflow, often caused by dirty filters or blocked vents. When the airflow over the coil is inadequate, the coil can get too cold, leading to ice buildup.

To handle a frozen evaporator coil, follow these steps:

  • Turn off the AC: Prevent further damage by switching off the unit immediately.
  • Check and replace filters: Dirty filters restrict airflow, so clean or replace them regularly.
  • Inspect vents and registers: Ensure they’re open and unblocked to maintain proper airflow.
  • Defrost the coil: Let the coil thaw naturally, which may take several hours.
  • Call a professional: If the problem persists, contact an HVAC technician for a thorough inspection.

Thermostat Malfunctions

Thermostat malfunctions can greatly impact your AC’s performance, leading to inconsistent temperatures and inefficient operation. One common issue is faulty wiring, which can prevent the thermostat from communicating with the AC unit properly. If you notice that the AC isn’t turning on or off when it should, or if the temperature displayed on the thermostat doesn’t match the room’s actual temperature, you might have a wiring problem. It’s best to call a professional to inspect and fix any faulty wiring.

Incorrect thermostat settings can also cause problems. Double-check that your thermostat and the desired temperature are set to the correct mode (cooling, not heating). Sometimes, settings can be accidentally changed, especially if the thermostat is in a busy area where buttons might be pressed unintentionally.

Additionally, ensure the thermostat is located away from direct sunlight, lamps, or other heat sources that could give false temperature readings. If the thermostat is outdated, consider upgrading to a more modern, programmable model. This can help maintain consistent temperatures and improve overall efficiency. By addressing these issues, you can ensure your AC system runs smoothly and reliably.


You can transform a sweltering, frustrating day into a cool, comfortable one by understanding and addressing common AC issues like sudden loss of cooling, strange noises, and water leaks. Regular maintenance, like changing air filters and checking for refrigerant leaks, guarantees your AC runs smoothly. Don’t ignore thermostat malfunctions or electrical problems; fixing them promptly avoids bigger issues. Being proactive keeps your indoor environment pleasant and saves you from costly repairs down the line.

Frequently Asked Questions

How Often Should I Schedule Regular Maintenance for My AC Unit?

You should schedule regular maintenance for your AC unit twice a year. This guarantees proper filter cleaning and thermostat calibration, keeps your system running efficiently, and prevents unexpected breakdowns during peak usage times.

Can Power Surges Damage My Air Conditioning System?

Yes, power surges can damage your air conditioning system. Electrical spikes and circuit overloads can fry sensitive components, leading to costly repairs. Installing a surge protector can help safeguard your AC unit from these issues.

What Are the Signs of a Refrigerant Leak?

You might have a refrigerant leak if you notice unusual noises from your AC or see ice buildup on the unit. Decreased cooling efficiency and higher energy bills are common signs of a leak.

Is It Normal for My AC to Run Constantly During Hot Weather?

Yes, it’s normal for your AC to run constantly during heat waves, especially if your thermostat settings are low. To reduce strain, adjust your thermostat a few degrees higher. This helps maintain efficiency and comfort.

How Can I Improve My AC’s Energy Efficiency?

Upgrade your home’s insulation to reduce heat transfer to improve your AC’s energy efficiency. Install smart thermostats to optimize cooling schedules and monitor usage. These steps help maintain a comfortable temperature while saving energy and money.

Cassie Pound, owner of Quality Heating, Cooling, Plumbing & Electric
Published by
Cassie Pound

Cassie Pound is the Vice President of Quality Heating, Cooling, Plumbing & Electric with locations in Tulsa, Glenpool, and Bartlesville, Oklahoma.