Cold storage warehouses store food after production and before foods are transported and distributed to supermarkets or catering establishments. Food is stored either chilled or frozen and may remain in the store for periods of a few hours, days or even a year (for some fruits and vegetables) in chillers and up to several months in freezers. This sector has been shown to be one of the sectors of the cold chain where the temperature of products is well temperature-controlled. Energy usage is important to cold store operators as it is a high proportion of the overall operating costs. Cold storage warehouses traditionally have high usage of low global warming potential refrigerants.