Undercounter Dishwashers Level Up

Turn here for intel on the latest undercounters, now with two-rack options, upgraded efficiency standards and more.

Dishwasher LXn Hobart Warewash 094 SM
At least two makers now offer undercounter dishwashers with two racks, enabling operators to clean more dishes at once. Both models are Energy Star rated, too. Courtesy of Hobart.

When it comes to foodservice equipment, undercounter dishwashers play the classic supporting role. They may never take center stage—like an oven, a broiler or even a blender—but they help an operation’s overall performance shine.

Tucked under a counter, these machines are understated equipment, even compared to conveyor or door-type dishwashers. Yet, they’re indispensable for many small foodservice operations, providing load after load of sanitized, spotless plates and crystal-clear glassware. Undercounter dishwashers are especially popular at coffee shops, bars, small restaurants and other space-limited operations.

If you haven’t purchased an undercounter dishwasher in the past five-or-so years, you’ll find that the latest models have new features designed to improve efficiencies and offer an attractive return on investment. New models offer higher throughput, thanks to the introduction of two-rack machines, and improved energy efficiency, in accordance with updated Energy Star criteria. In addition to tackling soiled plates and sticky glassware, the newest dishwashers are taking on labor challenges with features that make them easier to use and maintain, requiring less training upfront.

A New Level of Clean

A standard residential dishwasher has an upper and lower rack, but until recently commercial undercounter dishwashers offered only one level. The obstacle was the ability to get a thorough clean on two racks in a commercial machine’s brief wash cycles—around two to three minutes. Two manufacturers say they’ve cleared that hurdle, and recently introduced dual-rack undercounter dishwashers. These machines offer increased throughput by expanding rack space and promise to improve labor efficiency with fewer loads. One two-level model can clean up to 48 racks per hour, offering one of the industry’s fastest undercounter throughput rates. Before specifying a two-rack machine, consider whether your ware volume warrants a second level.


One maker’s two-rack unit is NSF certified to wash glassware or cups on both racks. Courtesy of Champion.

Some competitors are dubious that a two-rack dishwasher can perform sufficiently. They are holding off from introducing a second tier because of continued concerns that it would impede washing effectiveness. That said, the new double-rack machines have passed NSF’s cleaning requirements. (See “The Buttermilk Test” below.)

If you’re in the market for a double-level machine, consider what items you will be washing on each rack. One manufacturer offers a model that is NSF certified for glasses and cups on both racks. In contrast, the other manufacturer offers the only double-rack machines with an NSF-certified pot-and-pan cycle. The top rack on that product line is a wire rack designed for ceramicware and silverware, not glasses. With both brands, the upper rack can be removed to accommodate larger wares.

The Buttermilk Test

Fresh milk in glass pitcherCommercial dishwashers undergo stringent testing—including the buttermilk test—to earn NSF certification for meeting minimum requirements for sanitation and cleaning. The buttermilk test checks the machine’s ability to remove a dry coating of buttermilk from plates and glasses. A coating of buttermilk is applied to the top surface of glazed china dinner plates and milk glasses and air dried at 100°F for 17 hours. The coated wares are then washed in the model being tested. After the wash, NSF visually inspects the surface of the plates and glasses for any remaining buttermilk or detergent. Only machines that sufficiently remove the buttermilk coating can be certified as having met the dishwashing requirements of NSF/ANSI Standard 3 for Commercial Warewashing Equipment.

Energy Star Shines On

Today’s Energy Star-certified dishwashers are more efficient than ever, meeting Version 3.0 requirements that went into effect July 2021. The new standards slash the idle energy limit to 0.25 kW for low-temperature undercounter units, and 0.30 kW for high-temp units; both previously had 0.50 kW limits. Version 3.0 also introduced a wash energy metric, which is the rate of energy consumed by the dishwasher while “washing” or “sanitizing” dish loads. Several manufacturers have upgraded their dishwashers to meet these new specs, and new products continue to come to market—with one company releasing its high-temp Energy Star Version 3.0 model this summer.

Energy Star-certified dishwashers typically have a higher price tag than noncertified products, although manufacturers say the differential is not as significant as with other equipment. In turn, you’ll save on energy and water usage costs. Some local utility companies offer rebates for Energy Star-certified dishwashers. Be sure to check whether the states/municipalities you operate within require newly installed commercial dishwashers to be Energy Star certified.

Version 3.0 recognizes products with innovative heat recovery technologies, like those that recycle steam energy, using it to preheat incoming rinse water. This technique offers ventless operation and can work off of cold water, eliminating the need for a hot water supply to the dishwasher. The bonus: With much of the steam recycled, crewmembers won’t face a huge plume of steam when they open the machine. If the undercounter is in a customer-facing setting, like behind a bar, guest comfort also is improved. Heat recovery technology was first introduced on undercounter units about a decade ago, and is now offered by several manufacturers.

Ease of Use and Maintenance

Manufacturers continue to make their dishwashers easier to use and maintain, with features like intuitive touch screens. Automatic fill is now widely available in response to consumer demand for simpler operations, with another manufacturer adding the capability to its newest model that will debut at the National Restaurant Association Show in May. These units fill with the simple touch of a button. In contrast, models with manual fill require crewmembers to hold a button until the machine is filled.

When it comes to maintenance, deliming is essential to remove scale and keep the dishwasher working optimally. To help, some models alert the operator when it’s time to delime, based on machine usage and water hardness. Several brands offer delime cycles, and at least one manufacturer offers an auto-delime feature that, when selected by the operator, will dispense the appropriate amount of the deliming agent. This saves staff from having to handle the chemical and ensures that the correct amount is used.

Several models offer built-in diagnostics for troubleshooting to help identify issues quickly. You’ll also find displays that identify temperature and cycle times. At least one manufacturer offers an app with temperature monitoring, water and chemical consumption, alerts and troubleshooting.

Six Specs

Before specifying an undercounter dishwasher, determine whether it’s the right equipment for your operation’s dishwashing demands. A common mistake is purchasing an undercounter unit, when a larger door-type dishmachine is needed. If an undercounter unit fits your needs, consider these six specifications:

1. Capacity. How many racks do you need to clean per hour, during peak times? Options range from roughly 24 racks per hour to 48.

2. High-temp vs. low-temp. High-temperature machines use a 180°F rinse to sanitize wares, while low-temperature machines rely on chemicals. Each produces slightly different results. For example, glasses dry quicker with a high-temp machine, but they need time to cool. High-temp machines perform better at removing greasy stains, including lipstick marks. Low-temp machines may leave minute chemical residue. Often the determining factor is a facility’s electrical connection. High-temp machines require a 208-240V electrical capacity. If your facilities are wired for only a 115-120V connection, you’ll need to specify a low-temp unit.

3. Gravity drain vs. pump drain. A gravity drain relies solely on the force of gravity to remove wastewater from the dishwasher to a drain below. A pump drain is needed if the drain is level or above the waste outlet of the machine, and must be pumped away.

4. Size. Most undercounter units are 24 inches wide and 25 inches deep, but there are some outliers. When it comes to height, there’s more variability. If your countertops are lower than standard, an ADA-compliant dishwasher might be your best fit, as they’re designed to slide under a counter height of 34 inches.

5. Items being washed. Do you need a cycle that can tackle pots and pans that have baked-on residue? If you’re washing pots and pans, you’ll also want to specify a chamber size and door opening that will easily accommodate them. If glassware is among the items being washed, consider a unit with a soft start that protects against chipping and breaking by reducing the initial pressure from the wash pump. If you’re washing only glassware, consider a glasswasher, rather than a traditional undercounter dishwasher. These units have a smaller opening, which means that when the door is open, you’ll have more clearance. The opening also is slightly higher than in a traditional dishwasher, improving ergonomics for most team members.

6. Construction. Among other factors, consider whether you want double-wall construction. This feature offers extra insulation, meaning a quieter wash and cooler operations—especially important if your dishwasher is in the front of the house.

A solidly constructed and well-maintained undercounter dishwasher can play its supporting role for 10–15 years, or even more, making load after load of your wares sparkle clean.

Keeping Up

Some of the newest undercounter dishwashers boast improved efficiencies. Turn here to compare six makers’ latest specs.



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