The greening of America’s diner

A light-bulb moment saves a Denny’s franchisee $20,000 in energy costs.

Joe Terrell became passionate about energy conservation after a fateful day when he had to change a light bulb in his restaurant, a Denny’s franchise in Mokena, Ill.

“While searching for a replacement, I came across a compact fluorescent light bulb,” Terrell writes on his website “After some research, I learned that a CFL bulb produces 20 percent more lumens in light than a 100-watt bulb. I immediately replaced all our bulbs, which saved $440 a month. Since then, I have been on a quest to be as energy efficient as possible.”

His quest led him to work with folks at the National Restaurant Association and Environmental Protection Agency to establish energy-saving standards for restaurants, with 2,200 operations now involved in the initiative. But Terrell became personally invested when he made plans in 2008 to open a second Denny’s in Joliet, Ill., and decided to pursue LEED certification.

Terrell took his first certification steps during construction, using recycled steel beams, stainless steel shelving, drywall and wood paneling and renewable floor and ceiling tiles. He researched and tested energy-
efficient equipment and lighting in the Mokena store before making purchases for Joliet. In the end, his Joliet restaurant became the only Denny’s franchise to achieve LEED certification. And in the first 12 months of operation, utility costs in Joliet were $20,000 less—20 percent lower—than those at his Mokena location. Terrell details the choices that helped him achieve those savings.

Instant-on water heaters

In Joliet, two tankless water heaters replace a conventional 100-gallon water heater, heating 17 gallons of water on demand instead of all the water at once. Terrell says many operators overlook hot water as an “energy bandit,” but this is an important piece in the push for increased efficiency.

Bottom-up ice machine

Terrell’s ice machine saves energy in two ways. First, he had the compressors installed on the roof instead of in the kitchen, so the area around the machine doesn’t get too hot. Second, the machine is designed to remove ice from the bottom; most machines take ice from the top, and the bottom ice gets dirty and must be discarded. It takes water and energy to melt the ice, clean the machine and refill it, he says.

Step-down exhaust hood

The hood Terrell installed measures the amount of heat that is being generated by the grill, fryers and griddle and automatically adjusts the airflow and the fan. The hood isn’t working when it doesn’t need to be (during slow periods in the kitchen, for example), saving on energy usage.

Harvesting daylight

Terrell installed six skylights in the building, allowing him to keep most of the LED lights turned off during the day. Plus, the LED lights have dimmers that measure the light and adjust up or down based on how much daylight is coming in. Terrell admits this was an expensive effort (almost $20,000 for skylights, $5,000 for LED lights), but he believes it was worth it based on all the money this Denny’s has saved.

Recycled dishwasher water

Terrell’s dishwasher uses water from the last rinse on the first wash of the next batch of dishes, which saves more than a 100,000 gallons of water per year. He also specs a hose with a pressure of 60 psi, saving about 30,000 gallons of water a month. The hose removes enough food waste to avoid an extra run through the dishwasher, Terrell says. 

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