I built Helge's fridge from plywood and mahogany. It has six inches of insulation and a vacuum sealed door (made by Glacier Bay). The Isotherm compressor and holding plate assembly are made in Sweden. The compressor's speed varies depending on the system's load. This allows it to "sip" electricity when the demand is low. With 87 degree days and 70 degree nights, the fridge draws only 16 amp/hours.