There are numerous opportunities available to improve the energy efficiency of a walk-in refrigerator.

There is currently no Energy Star rating for walk-ins, however, the U.S. Department of Energy is working on standards that are expected to be announced in 2012 and implemented by 2015.

Energy-efficient ratings for these units are based on R factors, which denote the insulation of the panel. These typically range from R32 to R48, with the higher numbers offering greater insulation.

Although more expensive, walk-in panels with foamed-in-place polyurethane insulation offer the best R-value and are the most energy efficient, which can save money over time. Optional 5-inch and 6-inch-thick panels provide a greater R value.

Polyurethane panels meet or exceed all the efficiency requirements of the Federal Energy Independence and Security Act of 2007. Additionally, the foam insulation used in polyurethane panels is green friendly and free of CFC/HCFC.

Electronic controllers for refrigeration systems with reverse cycle defrost offer the optimum operating efficiency. Such systems can save up to 27 percent in energy usage over traditional mechanical systems.

Energy-saving options include automatic door closers, strip curtains at doors, high-efficiency lighting and high-efficiency motors on condensing units and evaporator fans.

Alarm/light management systems warn staff when doors are left open and automatically turn off lights after a specified time, conserving energy.

Anti-sweat control modules are designed to save energy by turning off glass door and frame heaters when no door heat is necessary.

Electronic and LED lighting introduces less heat into the walk-in, which can reduce the workload on the refrigeration system's compressor and help conserve energy.