Air Conditioning Capacitors

Air Conditioning Capacitor

An air conditioning capacitor is the AC capacitor in your air conditioning system that stores and releases electrical charge to start and run the fan motor and compressor. In HVAC systems, this small cylindrical electrical component is a common cause of units that will not start, hum, or trip out, so getting the right replacement matters for safe operation, system efficiency, and reliable performance.

Star Sparky stocks replacement capacitors for split systems across Australia for air conditioner owners, technicians, and capable DIY customers who need to identify or replace the part correctly. The range covers the common types: run capacitors that keep ac motors turning efficiently, and dual run capacitors that support both the fan and compressor in one space-saving component, with a range of uF (microfarad) ratings and voltages to suit different models. Housed in a durable metal can, each capacitor uses a dielectric material to store the charge that gets your motors up to speed.

Choosing the right capacitor comes down to matching the correct microfarad rating and voltage to the original part, since the wrong specification can stop the motor from starting, damage components, or reduce performance.

Replacing a capacitor is electrical work. While the part is inexpensive, fitting it should be done by a qualified technician, as capacitors hold a charge even when the power is off. Shop the rating you need below, or call 1300 996 996 for advice on matching a part. The FAQs cover the common questions.
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  • 35uf Aircon Capacitor CBB65

     $16.99

  • 25uf Air conditioning/Fan Capacitor CBB65

     $15.99

  • 50uf Aircon Capacitor CBB65

     $19.89

  • Air Conditioning Capacitor 1.5uf CBB61

     $6.99
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    Air Conditioning Capacitor CBB61 5uf

     $10.99 $14.99 Save $4.00

  • 60uf Aircon Capacitor CBB65

     $21.89

  • Air Conditioning Capacitor CBB61 - 2.5uf

     $7.99
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    Air Conditioning Capacitor CBB61 3uf

     $8.99 $12.99 Save $4.00

  • Air Conditioning Capacitor CBB61 3.5uf

     $9.53

  • 15uf Air conditioning/Fan Capacitor CBB65

     $14.29
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    Fan capacitor | (1.6~2.3uf)

     $8.99 $16.98 Save $7.99

  • Air Conditioning Capacitor 1uf CBB61

     $5.99

  • 70uf Aircon Capacitor CBB65

     $22.29

Scroll through our range now and find the right air conditioning accessories for you today!

Frequently Asked Questions
What does an AC capacitor do in an air conditioner?

A capacitor stores electrical energy and releases it to start and run the air conditioner’s fan motor and compressor. It provides the jolt needed to start the motors and helps them run smoothly, which is why a failed capacitor often stops the unit working. The charge is held across a dielectric material inside the sealed can, then released to bring the motors up to speed.
How do I know if my air conditioner capacitor is faulty?

Common signs of a faulty capacitor include the unit not starting, weak cooling, a humming noise without the fan turning, the lights dimming when the air conditioner turns on, the system tripping the breaker, or the fan or compressor struggling to start. 

AC capacitors store energy and release an initial burst to help the motors start, then support smooth running. A technician can diagnose the issue with proper testing using a multimeter that measures capacitance; if readings are significantly lower than the rated value, replacement is usually needed. 

Most capacitors last between five and twenty years, so an older unit that is struggling is a common candidate for replacement.
What size capacitor do I need?

Match the microfarad (uF) rating and voltage to your original capacitor. The specification is printed on the side of the old part or listed in the unit’s documentation, and the capacitance in microfarads needs to match the compressor or fan it serves. Some systems also use start capacitors, which provide the extra surge needed to get a motor turning at startup. 

Visual signs of failure can include a bulging top, leaks, or scorch marks, so it helps to locate and verify the old part’s rating and shape before ordering. A weak part can also reduce cooling performance and lead to higher electricity bills because the system uses more energy. 

Using the wrong rating can damage the motor, so a qualified technician should confirm the voltage and rating and install a new capacitor only after testing with a multimeter.
What is the difference between a run and a dual run capacitor?

A run capacitor serves a single motor, such as the fan, and capacitor size is measured in microfarads (uF), so the replacement should match the original rating and voltage. Dual run capacitors combine two capacitors, or two capacitance ratings, in one housing for the compressor and fan, which is common in many split systems. 

Start capacitors are a separate category used where extra starting torque is needed, and they are typically rated 70 mfd and above. Matching the correct specs, including the physical shape that fits your unit’s bracket, helps ensure the fan motor and compressor start and run properly. Check what your unit uses before selecting a new capacitor with the original specifications.
Can I replace an air conditioning capacitor myself?

Replacing a capacitor is electrical work on an air conditioning unit and should be done by a qualified technician. Many systems use dual capacitors, which combine two capacitors in one housing to serve both the compressor and fan, and proper safety matters because capacitors store a charge even when the power is disconnected. 

Before any work, the technician should use the disconnect switch to shut off power, open the access panel, identify the wires and capacitor terminals, and discharge the part safely with an insulated screwdriver so the connections can be checked before a new capacitor is connected. 

Using the correct replacement and professional service, along with a check of the motor’s resistance, can also help extend the life of the system.
How much does it cost to replace an air conditioner capacitor?

The capacitor part itself is inexpensive, which is why replacing it is one of the more affordable air conditioning repairs. A full professional replacement, including the technician’s labour, typically costs somewhere in the range of $100 to $400 depending on the unit and the callout. 

Buying the correct capacitor and having it fitted during a routine service is usually the most cost-effective approach.