Is your air conditioner acting up lately? Check if the problems are caused by bad AC capacitor symptoms.

Your air conditioning unit plays a vital role in blowing cold air and keeping your indoor environment comfortable. But like any other mechanical system, it is prone to malfunctions. And one of the most common issues you’ll face are failing AC capacitors.

The AC’s capacitor is responsible for powering your unit’s motor. If it fails, it can cause a wide range of problems that affect the performance and efficiency of the entire air conditioning system.

So in this article, we’ll discuss 12 of the most common bad AC capacitor symptoms to watch out for.

AC Not Turning On

When the capacitor is faulty, the motor will not receive enough power to operate. This will cause the air conditioner to not turn on (or it may still turn on, but only intermittently).

A bad capacitor may also cause the motor to work harder than necessary, leading to a shorter lifespan for the motor and your HVAC unit as a whole. It may even cause your unit to trip its circuit breaker, the safety mechanism designed to prevent damage to the system.

Weak Airflow

Through defective capacitors, the motor will struggle to operate at full capacity. This will lead to reduced airflow from the AC units.

This also causes your air conditioning system to work harder than necessary to produce cold air, resulting in higher energy consumption and increased wear and tear on the system over time. To top it off, weak airflow will make your indoor environment less comfortable, as the AC system may not be able to distribute cool air throughout the space effectively.

Frequent Cycling

A bad AC capacitor can also cause frequent cycling, which is when the AC unit turns on and off more frequently than normal. Frequent cycling can put a strain on the HVAC system and cause unnecessary wear and tear, leading to decreased efficiency and increased energy consumption.

Additionally, frequent cycling can cause the new or aging AC unit to take longer to cool the indoor environment. This leads to discomfort and inconvenience for the occupants.

AC Compressor Not Running

Bad AC capacitors can also cause your air conditioner unit’s compressor to stop running. This can lead to a significant decrease in the system’s cooling capacity. In short, it will prevent your entire system from cooling the indoor environment effectively.

Furthermore, if the compressor is not running properly, it can cause other components of the AC unit to malfunction. This can lead to further damage and increased repair costs.

Warm Air Blowing From Vents

A defective AC capacitor can cause your system to blow warm air instead of cold air as well. Again, this is due to the motor and compressor not receiving enough power to operate efficiently.

Unchecked, this can make the indoor environment very uncomfortable, especially during hot weather. Additionally, a faulty capacitor can cause the air conditioning system to overwork, leading to increased energy consumption, reduced lifespan of the system, and higher repair costs.

Loud Humming or Buzzing Sound

Loud buzzing or humming noise can be an indication that the air conditioning capacitor is failing (if it hasn’t already). These sounds can occur when the capacitor is not providing enough electrical energy to the motor and compressor, causing the system to struggle to operate.

These buzzing or humming noise can be a warning sign that the system is not operating correctly and may require professional attention. Ignoring these symptoms can lead to further damage to the AC system and may result in costly repairs or replacement.

Unusual Odor

A failing AC capacitor can cause the system to give off an unusual odor, another warning sign that the capacitor is failing or has already failed. This usually occurs when the capacitor overheats, leading to a burning smell that can be unpleasant and concerning.

Overheating can also happen when the capacitor is not providing enough electrical energy to the motor and compressor, causing the system to overwork and generate excess heat. Bear in mind that unusual odors can also be an indication of other HVAC system issues, such as mold growth or a clogged air filter.

Higher Electricity Bills

When the air conditioner’s capacitor is not functioning correctly, the AC system may require more energy to operate. This will eventually cause an increase in electricity usage and higher energy bills.

Moreover, if your AC system is struggling to cool the indoor environment, it may need to run for longer periods to reach the desired temperature. This will exacerbate your voltage rating and billing problem even further.

Malfunctioning Circuit Breaker

A fault air conditioner capacitor can also cause problems between the AC system and its circuit breaker. When the capacitor is failing, your air conditioners may draw more electrical current than it should. This causes the circuit breaker to trip and cut off power to the system.

Malfunctioning circuit breakers can be frustrating and inconvenient for homeowners. That’s because it can disrupt the cooling of the indoor environment and require a reset of the circuit breaker.

AC Unit Freezes Up

When the capacitor is not providing enough electrical energy to the motor and compressor, it can cause your air conditioning system to overwork and generate excess heat. This heat can cause moisture to build up on the evaporator coils, leading to ice formation and reduced airflow.

A frozen AC system can result in reduced cooling capacity, increased energy consumption, and higher repair costs. Addressing a faulty capacitor promptly and regularly maintaining the AC system can help prevent these issues and ensure that the indoor environment remains comfortable and healthy.

Motor Overheating

A bad capacitor can cause the system’s motor to overheat. This is largely due to the AC’s motor drawing more electrical current than it should.

Additionally, an overheating motor can lead to premature wear and tear, reduced lifespan of the system, and higher repair costs. By neglecting to have your AC capacitor replaced, you might end up with worse problems.

AC System Shuts Off Automatically

Finally, a bad capacitor can cause the entire system to shut down automatically and unexpectedly. This automatic shut down is a safety feature designed to prevent damage to the system, as well as help you avoid potential safety hazards.

So once you notice that your AC shuts down during inconvenient times, that’s a sign you need to find a replacement capacitor.

Wrapping Up

In conclusion, it’s essential to keep an eye out for the bad AC capacitor symptoms to ensure that your air conditioner runs smoothly (and without risking damage or safety hazards). Whether it’s weak airflow, warm air, high energy bills, unusual odors, or frequent cycling, these symptoms can indicate a failing or failed capacitor that needs to be addressed promptly.

Regularly maintaining your air conditioner unit, including getting AC capacitor replacement, can help prevent these issues and keep the indoor environment comfortable and healthy. By being aware of these symptoms and taking prompt action when necessary, you can ensure that your new or aging HVAC system operates reliably and efficiently throughout its lifespan.



How do I know if my AC capacitor is bad?

If your AC won’t start, is making strange noises, or is running but not cooling properly, it may be a sign that your AC capacitor is bad. A visual inspection may also reveal signs of a swollen, leaking, or corroded capacitor.

What happens to AC when capacitor goes bad?

When an AC capacitor goes bad, the AC unit may fail to start or not cool properly. The compressor and fan motors may also overheat, leading to potential damage to the AC unit.

How do you diagnose a bad capacitor?

To diagnose a bad capacitor, you can perform a visual inspection for signs of swelling, leakage, or corrosion. You can also use a multimeter to check the capacitor’s capacitance and resistance values, or perform a “hard start” test to determine if the capacitor is able to provide enough power to start the compressor.

Will AC turn on if capacitor is bad?

If the AC capacitor is completely failed, the AC unit will not turn on. However, if the capacitor is only partially failed, the AC unit may turn on but not function properly.

bad AC capacitor symptoms