An AC capacitor is a cylinder-shaped device in your air conditioner that energizes the motor and gets the compressor running. When you turn on your AC, the capacitor sends a strong initial jolt of power to the motor to start the cooling cycle. Once your AC is operating, the capacitor starts to produce less energy or switches over to a different capacitor that can continue to provide a steady stream of power until the cooling cycle is complete.
Although your AC unit is powered by the same grid that powers your home, it needs a large amount of energy to work effectively. The capacitor compensates for the relative weakness of your residential electrical system.
An AC capacitor’s functional abilities are measured in voltage and microfarads. Voltage measures how much work is needed to move electrical current through the capacitor. Generally speaking, higher-voltage capacitors move electrical current more quickly. The maximum amount of voltage that can pass through an AC capacitor is given by its voltage rating, which is typically rated for 440 volts.
Microfarads measure capacitance, the capacitor’s ability to store electrical current. Most AC capacitors have a capacitance rating of 5 to 80 microfarads.
AC capacitors may look like batteries, but the devices are not the same. Batteries convert chemical energy to electrical energy and discharge gradually, while capacitors store energy in an electric field and discharge quickly to transfer energy between circuits. Furthermore, AC capacitors are high-voltage devices that can be dangerous if they’re handled improperly, even when the power to your AC is shut off and disconnected.
What Kinds of Capacitors Run ACs?
AC units come in a variety of builds that use different kinds of components. Your unit may use two single capacitors or one dual capacitor to run.
Units that have two single capacitors use a start capacitor and a run capacitor to work properly. The start capacitor delivers energy to the motor to start the AC cooling cycle, then switches over to allow the run capacitor to keep the motor going at a constant rate.
A dual capacitor offers the same functionality as the start capacitor and run capacitor but in a more convenient package. They tend to save space in your AC unit and are often easier to replace.
What Are the Signs of a Bad Capacitor?
Capacitors are essential, hard-working devices that your AC can’t do without. Failing capacitors can cause a variety of problems that will lead to AC malfunctions, resulting in decreased cooling power. If the AC capacitor fails to power the compressor, it will not work as designed.
If you notice any of the signs listed below, you might need to replace your AC capacitor:
- The fan doesn’t turn on
- The fan speed is slow
- The fan is not very powerful
- The AC capacitor fails to complete the cooling process
- The AC unit gets really hot
- The system takes a long time to cool down
- The capacitor swells or bulges outward, disintegrates, or spills oil
How Much Does It Cost to Replace an AC Capacitor?
If you need a new AC capacitor, you’ll probably need to spend between $120 and $250 for parts and installation. The cost can vary depending on your model and location and be as high as $400 in some places.
When you need to replace an AC capacitor, it’s important to call a professional. Replacing the capacitor yourself can be dangerous, and removing it improperly could lead to shock or electrocution. A qualified technician will be able to safely remove your faulty capacitor, replace it with a new one, and get your AC running smoothly.
Keep Your Air Conditioner Running Smoothly With a New AC Capacitor
If you notice that your air conditioner runs in fits and starts, it may be time to replace your AC capacitor. The professional HVAC technicians at Melbourne One Hour can fully inspect your system and safely change your AC capacitor so you can relax in cool comfort all year long.