Learn more about air conditioner capacitors and why they are essential to the system.
Beneath the tangle of wires in your air conditioner’s outdoor unit lies one of the essential components of the entire HVAC system: your air conditioner condenser.
Resembling a shiny, cylindrical battery, AC capacitors power the AC system’s motors and power them as you cool your home.
AC capacitors are one of the most commonly replaced parts of air conditioners. This is primarily because the HVAC system can stop working if a capacitor fails or malfunctions. When this happens, the air conditioner has to do more work to circulate cool air through the room, which can eventually wear the air conditioner out and lead to higher utility bills. Learn everything you need to know about AC capacitors, including how to spot early signs of trouble, AC troubleshooting tips, and what to do if your capacitor fails.
But first, a quick warning:
AC capacitors are dangerous high-voltage devices. Touching or mishandling can result in serious injury or death. So please don’t touch them. Consult her experienced and licensed HVAC technician whenever you have problems with your air conditioner.
What exactly do AC capacitors do?
AC capacitors provide the initial surge that air conditioner motors need to operate correctly. It stores electricity and sends it to the system’s engines in powerful bursts, spinning the device as the cooling cycle begins. When AC power is applied, the capacitor reduces energy output but provides constant current until the process is completed.
AC capacitors are measured in volts and microfarads. Voltage indicates the amount of current flowing through the capacitor. The higher the voltage on the capacitor, the faster the current will flow. Microfarads, on the other hand, describe how much current a capacitor can store. Most capacitors range from 5 MFDs (microfarads) to 80 MFDs.
Although it looks and functions like a battery, a capacitor is not a battery. They are connected to the wiring of the air conditioner. You can’t just open the device door and plug in a new capacitor when replacing it. AC capacitors are high-voltage devices and can cause serious injury even when the power is off, so do not replace them yourself. More on this later.
Why do we need capacitors?
Even though an AC unit is plugged into your home’s electrical system, it must be amplified to work effectively. This is because air conditioners are heavy-duty machines that require a lot of energy to do their job, and the wiring in your home doesn’t provide sufficient power to get the job done. It compensates for this by starting the system’s motors and helping to cool the house until you take a short break. The condenser will work again when it’s time for another cooling cycle. Capacitors do an essential and tiring job. That’s why condenser failure is one of the most common reasons air conditioners don’t work, especially in the summer. A worn-out AC capacitor can cause a common problem you probably want to avoid.
Start Capacitor and Run Capacitor: What is the difference?
Depending on how the HVAC system is set up, the outdoor unit may contain two single capacitors or one dual condenser. A system that requires two separate capacitors needs a start-up capacitor and a run capacitor to function correctly. A starting capacitor provides the energy an AC motor needs to start the refrigeration cycle. That’s it. When the device receives the first shock, the run capacitor is activated. It stores and releases the energy needed to keep the engine running and burn out the air conditioner. If one of these capacitors fails, the technician may decide to replace both parts with a dual capacitor.
A dual capacitor is like a combo pack of candy bars. The device performs the same task as the starting and running capacitors. It gives your device that all-important first spark and supplies a constant flow of electricity to keep it moving. Dual capacitors are much more convenient. It saves space in your HVAC unit and is easy to replace by HVAC technicians.
What are the signs of a bad AC capacitor?
Some signs tell you when you need to hire an HVAC technician to replace your AC capacitors. Common symptoms of a bad capacitor include:
- The air conditioner takes a long time to start its cooling cycle or does not start at all
- The air conditioner turns off randomly
- You can’t feel the cold air in your house while the air conditioner is running
- A buzzing sound is heard when the air conditioner is running
- I can smell smoke or a burning smell coming from my device
- Your energy costs are unreasonably high
Bad AC capacitors can have many causes, some of which are:
Dirt hits the condenser and causes damage. Extremely high temperature causes overheating of the condenser. Wear and tear over a long period. Short circuits in cooling systems, power surges, and even lightning strikes.
How do you test AC capacitors?
If your AC capacitor is not working correctly and you need help determining if it needs to be replaced, please get in touch with your local Trane dealer. These trained professionals use specialized tools and training to measure capacitors’ current, voltage, and resistance. Don’t try this yourself, as messing around with capacitors can result in severe injury or death.
You should hire an HVAC expert to help you out.
How much does AC capacitor replacement cost?
According to a 2021 report by HomeAdvisor, he will spend $120 to $250 on parts and installation if he receives confirmation from his licensed HVAC professional that the AC capacitor needs replacement. Please be prepared. Prices may vary depending on the make, model, voltage, and effort required to install HVAC capacitors. (Branded devices tend to be more expensive, costing up to $400 or more.)
If you want to buy the parts yourself, you can spend anywhere from $9 to $45 on the solid capacitors, but certain brands and models of parts can cost more. Work and installation by his licensed HVAC professional can be a large part of the cost, and the dealer may not have the incentive to install the purchased parts themselves.
Can I replace the AC capacitor myself?
No, I can not. There are do-it-yourself AC maintenance tips, but it requires a skilled HVAC technician to replace the AC capacitors. A qualified technician has the experience to properly remove the faulty condenser and replace it with a new one to keep your air conditioner working properly.
Please find your nearest Trane dealer to help diagnose potential capacitor problems and safely replace them. If you’re unsure how your condenser is performing, regularly schedule maintenance with a technician to ensure your equipment is in the best possible condition.