My PO installed an EZ-Kold holding plate system. It has impressive energy consumption specs (only 30 to 36 Amp-Hrs per day), but requires a well-insulated box to achieve this. My icebox is unaltered from the factory, and has inadequite insulation, as with most production boats. I place a 1-inch foam panel on the countertop, and it gets quite cold underneath.
But the real problem is the wall up against the engine room. It gets HOT in there. I plan to inject foam behind the plywood, and then put another inch or two on top of the plywood. We'll see how it goes. Meanwhile, we use ice and the regrigeration together. Works much better than just ice alone.
