Once you've identified the capacitor, buy it from a retailer or hardware store that sells HVAC parts. However, before you buy a new one, make sure you read the label carefully.

Depending on the speed of your motor, you might also want to consider other factors, such as the voltage and frequency of the power supply.

Oftentimes, it is easier to replace the capacitor yourself, but it's always best to call a professional to get the job done properly. A good AC technician should be able to replace the capacitor without any issues.