Like its residential cousin, the refrigerator, the vending machine has the potential to be a sneaky Energy Hog or—for energy-wise businesses and agencies—the source of significant electricity savings.

According to Energy Star, there are around 3.4 million refrigerated beverage vending machines installed across the United States. Those machines operate 24 hours a day, seven days a week, each consuming between 2,500 to 4,400 kWh per year, or a total of more than 15 billion kWh annually.

Efficient Energy Star-rated models are available, so getting control of the load could be as simple as upgrading equipment—if facilities owned the vending machines. However, most machines are leased from the beverage manufacturer or a management company on multiple year contracts.

When a contract comes up for renewal, a business can request Energy Star machines in its request for proposals. Facilities in the middle of long-term contracts may be able to work with vending machine owners to upgrade their fleets. When those options weren't available to some Western customers, they found other ways to reduce their vending machine loads.

Control technology saves taxpayers money

The Colorado Governor’s Office of Energy Management and Conservation installed the VendingMiser energy control device on 200 cold beverage machines in state buildings in 2004.

The VendingMiser uses an infrared sensor that powers down a cold beverage machine when occupancy levels indicate no activity. The vending machine automatically powers up at appropriate intervals to keep the drinks cold, independent of occupancy.

The project started when the Colorado Department of Public Health and Environment was looking for ways to reduce electricity bills in its leased office space. Since the landlord controlled investment in building improvements, the facility manager concentrated on appliances and systems that were CDPHE property. "Lighting was an easy retrofit, for example," said OEMC Program Manager Susan Castellon, "and it turned out that vending machines could be controlled, too."

Following successful installation of VendingMisers at the CDPHE laboratory building, the CDPHE Sustainability Program conducted a test on nine beverage machines fitted with devices. These test machines used an average of 41 percent less electricity, for an approximate annual savings of $78 per machine. Beverage sales remained the same, and since the controllers, compressors and lights are used less, VendingMiser extends the life of the machine and reduces overall maintenance and repair costs.

"It was the logical conclusion," Castellon said. "If VendingMiser could save money for the Health Department, it could do it for others."

The Pollution Prevention Advisory Board, a governor-appointed panel that advises the CDPHE Sustainability Program, gave the OEMC a $30,000 grant to install 200 units in state agency buildings. The office worked with the Department of Human Services Business Enterprise Program for the Blind to pick the facilities that would benefit the most from VendingMisers. The BEP, which administers the state's vending machines, saw the installations as a great way to improve customer service while protecting natural resources.

OEMC provided education and installation information on VendingMiser to building managers to encourage their acceptance of the device. Health and Human Services and Personnel Administration are among the departments that received VendingMiser retrofits. Castellon estimates that the program saves Colorado taxpayers $15,600 each year.

University reconsiders measure

Not all state agencies wanted to participate in the program, added Castellon. "Colorado State University was getting a coincident peak rate from its utility [Fort Collins, Colo., Utilities], so the savings weren't that significant," she recalled.

Because an occupancy sensor operates the unit, the vending machine will only cycle off when occupancy is low, which is most likely during off-peak hours. "We weren't saving anything in demand charges," said CSU Utility Engineer Carol Dollard. "Shaving a few cents from off-peak prices couldn't justify the investment."

Then, in early 2006, Fort Collins Utilities introduced a new rebate on kilowatt savings. That caused CSU to take another look at VendingMiser. "The message is, 'incentives work,' " acknowledged Dollard.

It also helped that per-unit price for 154 devices was significantly less than what the university paid for the three VendingMisers it tested three years earlier. "Those factors combined to make the retrofit feasible," Dollard said. "Even so, $24,000 in annual savings still gets eclipsed by our more aggressive programs."

Data from plug monitors on the original vending machines reveal another factor that affects the VendingMiser's performance. The two machines located in busy hallways use only about 25 percent less energy. A third in an out-of-the-way break room saves the manufacturer's promised 40 percent. "Building owners need to look at traffic patterns when placing VendingMisers," noted Dollard. "You get the most benefit from machines in areas with low or sporadic occupancy."

School district tries different strategy

Predictable building occupancy helps Poudre School District control its vending machine loads without adding an energy control device.

PSD Energy Manager Stu Reeve clustered vending machines on school building automation systems, and took advantage of Fort Collins Utilities' time-of-use rates. While school is in session, vending machines run during the day and cycle off around 5 or 6 p.m. They come back on between 2 and 3 a.m. to make sure the drinks are cold for that first soda of the morning.  "The machines come on a little earlier for Monday," said Reeve.

The savings from that strategy are better than an energy control device, Dollard observed, but it wouldn't work at a university. "It's not unusual for students in dorms to be using vending machines at 3 a.m."

PSD tested the VendingMiser, but, like CSU, didn't see the expected savings. "Our rates are about 6 cents per kilowatthour, even with the wind power," said Reeve, referring to the utility's wind power program. "If a facility is paying eight to 10 cents, then the savings might be closer to the manufacturer's estimate."

Also, vandalism can be an issue if the VendingMiser is not placed in a protected area. "The unit sits next to the machine and it can be a tempting target," said Reeve.

Energy Star-rated machines remove the temptation by building the technology into the unit. PSD recently re-bid its vending machine contract, and made efficient machines one of the criteria.

Businesses can make their conventional vending machines more efficient, Castellon suggested, by delamping them—removing the light, where appropriate. CDPHE testing on machines that served only staff, and not the public, showed that delamping could save an additional 23 percent of energy use without affecting sales. "That’s nearly as good as an energy saving device, without a purchase price," she said.

Reeve summed up the reasons for targeting vending machines for energy savings. "We figure that each machine costs us about $200 to $240 annually," he said. "Whenever you take them offline, you get a piece of that back."