Why is my air conditioner so loud?

A majority of the time, it’s a dirty condenser, but check your filter first. If it is clogged up or dirty, replace it to see if that makes a difference in the sound. If the filter is really dirty, leave the AC unit off for approximately 15 minutes to make sure the A-coil did not freeze from the inability of air to blow through the unit. 

While you are waiting you can clean the condenser. In order to clean the condenser, turn the AC off at the thermostat, and go outside with your hose, not a power washer, and spray off the condenser for approximately 15 minutes until it is clean. That typically quiets the unit down. If this does not work, you likely need a service call.    

-Rich