I have a 2006 Sprinter 3500 that has been converted for video production use. We currently have a roof a/c unit but it pulls too much power to run when the rest of the on-board computers and equipment are running. I have considered separating its power input but that brings up other problems. I know that there is a rear air conditioner option but I have no idea how to go about finding one and an installer. Can anyone offer any suggestions. Thank you.