Best Practice Guide

Local Governments

Food Service

Sanitation and Water Use

Save water to save energy


For cafeterias, saving water—especially hot water—makes great economic sense. By conserving hot water you trim two bills: one for the water and another for the electricity or natural gas used to heat it.

Don’t ignore leaks. Water leaks are no small problem when it comes to energy efficiency. A leaky sink or dish machine, or a stuck solenoid valve, that loses one-tenth of a gallon per minute will waste more 50,000 gallons over the course of a year. If that same leak just happened to be hot water—you’d be spending hundreds of dollars heating water only to send it right down the drain!

Check your water temperature. Use a thermometer to make sure you’re water heater isn’t working any harder than it has to; hot water should be around 140 degrees at the faucet of the pot sink closest to the dish machine.

Add aerators. Hand-sink faucets can use as much as 10 gallons of water per minute when not equipped with energy-efficient water aerators. Outfit the hand sinks in your kitchen and bathrooms with low-flow aerators—you’ll cut water use and ultimately save on water-heating costs.

Add insulation. Heating water is a significant expense for most cafeterias. Fortunately, it’s relatively easy to reduce that expense by adding insulation to your hot-water system. Start saving by simply wrapping your hot-water pipes with the insulated covers available at many hardware stores.

Activate the automatic flue damper. Many commercial hot water heaters have an automatic flue damper that closes when the burners are off. This damper saves energy by blocking heat from escaping up the flue. Make sure that the damper motor’s switch is in the “on” position so that the damper will operate properly.

Control the recirculation pump. If your hot water system includes a recirculation pump, install a timer that turns the pump off when your kitchen is closed. You’ll reduce the heat loss from your hot water pipes, potentially saving hundreds of dollars on energy costs.

Switch to low-flow pre-rinse spray valves. Depending on the size and workload of your cafeteria, a low-flow spray valve could save you more than $1,000 annually. The secret to the low-flow valve’s success is its ability to save in three ways at once. By lowering your water consumption, the sprayer simultaneously slashes your water, wastewater-disposal and energy bills. And don’t worry, low-flow doesn’t mean slow—low-flow spray valves are engineered to work as well as or better than standard valves. As of January 2006, any new pre-rinse spray valves that you purchase are required by law to be low-flow models; however, thousands of old sprayers are still out there wasting water and energy. You may be able to replace your old valves for free by taking advantage of a give-away program through your local utility or water district. For more information and a list of qualifying low-flow pre-rinse spray valves visit www.fishnick.com/saveenergy/sprayvalves/

Dishwashers


From an operational standpoint, dishwashers are one of the most expensive pieces of equipment in your kitchen. Every rack of dishes you wash can include as many as eleven separate cost items within the three main categories of water, water heating and chemicals. Smart purchasing, operations, and maintenance can save you thousands of dollars in the dishroom.

Don’t waste the space! You’ll pay the same amount to run a halfway loaded dish rack as a fully load one, so make sure you only run fully loaded dish racks through the dish machine. Cutting wash cycles could save you hundreds of dollars annually.

Turn it off. High-temp dishwashers typically feature internal tank heaters. If you’ve got one of these dishwashers and you’re not turning it off at night, you’re wasting energy by heating water that you don’t need. The same holds true for booster heaters: turn them off at night to save. Finally, don’t forget to turn off the dishwasher exhaust hood while you’re at it!

Check rinse pressure. Pay attention to your dishwasher’s pressure gauge—if it’s showing pressure above 25 psi, there’s a good chance you’re using much more water than is necessary. Most dishwashers require only around 20 psi.

Check water temperature. Follow manufacturer specifications for tank temperature and rinse temperature.

Operate conveyers in auto mode. If you have a conveyer-style dishwasher, make sure you’re using it in auto mode, which saves electricity by running the conveyer motor only when needed.

Add or maintain wash curtains. Wash curtains—the plastic strips that hang on both sides of conveyer dishwashers—improve washing efficiency by trapping heat. Replace curtains when the old ones begin to fall apart.

Design your new dishwashing system with both energy and water efficiency in mind. If you’re in the market for a new dishwashing system, it’ll pay to look into energy-efficient gas booster heaters. Compared to a standard electric booster heater, a gas booster heater could trim energy costs significantly due to the relative lower cost of natural gas as a fuel, (though keep in mind that a gas booster heater could have a higher first cost and installation cost than the electric unit). Also, look for dishwashing systems that use one gallon or less of water per rack washed—typically, the less water required per rack, the less you’ll pay in energy costs.

Consider heat recovery. Refrigerant heat-recovery systems use waste heat from the walk-in refrigerators and freezers to preheat water that can be used in the kitchen. These systems are relatively simple and have reasonable payback periods when installed in kitchens with moderate to high hot-water needs.

Case in point: Merkl’s Deli & BBQ, Chula Vista
Merkl’s Deli & BBQ in Chula Vista was designed with energy efficiency in mind. Among other features, the deli is outfitted with low-flow spray valves, which perform as well as standard valves but save vast amounts of water and cut water-heating costs. “They work great,” reports Steve Wilson, one of the deli’s co-owners, speaking about the spray valves. “I’ve actually been able to turn the water pressure down with them.”

The California Urban Water Conservation Council (CUWCC) estimates that small and very small cafeterias can use low-flow spray valves to cut water-heating energy by around 7,600 kWh annually. In addition to saving hundreds of dollars on electricity costs, conserving 7,600 kWh would prevent nearly 12,000 lbs of CO2 from entering the atmosphere. For more information on spray valves, visit the CUWCC online at www.cuwcc.org.