Why don 12 volt and gas burning type refrigerators have energy star ratings?
The star rating system for refrigerators and freezers is limited to mains powered models of the “vapour compression type” (ie models that use a compressor and a refrigerant). Other systems such as DC, LPG and other absorption types of refrigeration systems are generally intended for the leisure and camping markets (although some are used on normal domestic households). Regulation of these products was not considered warranted (many are only used for a few weeks per year). As a general rule, absorption refrigeration systems are somewhat less energy efficient than vapour compression systems and usually provide less flexibility and control during operation.
