Running all day, every day, a vending machine uses a lot of energy. Vending machines are generally designed to be located anywhere, withstand the weather, and endure the occasional beating. Energy efficiency is usually not a high priority.
Consequently they use about ten times the electricity of a home refrigerator. Last year, the 56 vending machines on campus were costing Mount Holyoke about $27,000 a year to run, according to Todd Holland, Five College Energy Manager.
As a result of a recommendation from a working group drawn from the staffs of dining services and facilities management, 12 low-volume units have been removed recently from campus, saving the College $6,200 a year in electricity.
And, this summer, 26 machines were fitted with vending misers. A vending miser consists of a motion sensor and control box that shuts the machine down when nobody is near. This saves about 35 percent of the electricity required to run the unit. The controls measure ambient temperature to start the machine occasionally to keep the soda cold in warm weather. The controls also let the refrigeration system shut down normally to keep from harming the compressor.
The 26 machines are located in the residence halls, and in Blanchard, Kendade, and Kendall. Each has a sticker explaining how the vending miser works. Combined with the low-volume machine removals, this effort will save $10,000 a year.
"But money isn't all we're saving," Holland noted. "Saving electricity also saves the greenhouse gases that would have been generated by the plants that make our electricity. This effort will save 27 tons of CO2 per year, equivalent to taking five cars off the road or planting seven acres of trees."