Port side rear cockpit corner, also a few inches above the cockpit sole (opposite side of engine panel)...Have 2, one is dedicated to HVAC, 15k BTU Dometic unit. Installer said it was not required; however highly recommended. After returning from a sail, ladies like to go below and chat...95+ degree days demand that convenience or ladies may abort. I do everything I can to make things comfortable for them; if the ladies are happy, so goes the fellas!