I have the norcold conversion. Works like a champ. I recently added foil wrapped fiberglass insulation to the outside and what a difference it makes. Less frost, more cold, less run time. Plus the AC/DC switching is awesome. Dock power keeps it cold and reduces battery drain. I can run nearly 30 hours with it and my GPS/stereo/VHF/autopilot and not have to run the motor. Though I have gotten through an 8 day cruise off shore and ran the engine for about 2 hours a day, kept the batteries from going below 50%.Florida sail said:To clarify things: The boat that I am looking at is a Nonsuch Ultra, built by Hinterhoeller Yachts in Canada and does not have refrigeration. Adding insulation will probably be a must regardless. The Norcold conversion unit appears to be a possibility and if I want to spend significantly more $$ the Frigiboat conversion would be my choice. Oh well, decisions decisions.