Our article Undercounter Dishwashing vs. Manual Compartment Sinks addresses when it’s time to upgrade from a standard three-compartment sink to an undercounter warewashing unit, citing the following benefits of automated undercounter dishwashing:

  1. Better for the environment because they use less water than compartment sinks
  2. Better for your bottom line, saving users between $4,000 and $7,000 a year
  3. Better for food safety since the final rinse of 180°F kills 99.99% of microorganisms that lead to foodborne illness
  4. Labor savings, relieving the time-intensive task of manually washing by hand

As always, proper sanitation in any commercial foodservice business should always be Priority One. Though many facilities still opt for compartment sinks, the benefits of using a commercial dishwasher far outweigh the manual components associated with them. The questions posed here are which establishments are uniquely suited for an undercounter unit, and when is it time to upgrade to a door type dishwasher?

Undercounter vs. Door Type Dishwashers

“Unless it’s behind the bar, the only reason you’ll ever install an undercounter machine in a facility is space,” explains Steve Willoughby, Vice President of Sales and Marketing for Jackson Warewashing Systems, an industry-leading manufacturer of commercial undercounter, door type, and conveyor dish machines. “Door type dishwashers are the number one marketed machine, whether it’s a low temp or high temp unit. They’re going into any sit-down restaurant because it gives users much more flexibility.”

Flexibility is ultimately the biggest reason to opt for a door type dishwasher over an undercounter unit. This relates to throughput, measured by racks per hour. Door type machines can handle more, as well as additional types of wares, including food prep essentials like large mixing bowls, sheet pans, etc. With most undercounter units, you’re likely to get between 20 and 30 racks per hour. Most door type units, however, allow users to run through 65 racks per hour.

Says Willoughby: “Going with an undercounter dish machine over a door type is strictly a matter of necessity.”

Willoughby means space, a limiting factor for many establishments. If your commercial kitchen space doesn’t have room for a sophisticated dishwashing layout, you may decide to go with an undercounter unit. However, you’ll want to factor in how many guests you have dining in during peak hours, as well as dry time. Willoughby recommends approximating four guests’ dishes fitting in one rack. You can use this to begin calculating how many racks per hour will be efficient during rushes.

Dish room layouts incorporating a door type should make use of dish tables, and you should get the flow of your operation figured out before installing the machine. Dish tables provide space to organize and separate soiled ware from clean ware that needs to dry before re-entering circulation. A door type unit enables operators to wash more racks per hour, but they still need space to dry before being used again.

Commercial undercounter machines are not ideal for high-volume operations but work best in:

  • Coffee houses
  • Firehouses
  • Office spaces
  • Smaller restaurants
  • Behind bars
  • Daycare centers

Many restaurants may install both a door type machine in the kitchen space and an undercounter unit behind the bar to help bartenders quickly wash glassware. When installing an undercounter dishwashing unit behind the bar, it’s important to remember that bars are customer-facing environments, and many high temp units emit bursts of steam when opened. This can detract from the ambiance and be unpleasant for guests.

If you’re considering installing an undercounter unit in a direct, customer-facing environment, we recommend choosing a unit with steam elimination and energy recovery, like the Jackson SEER units. These units recycle the steam and use it to heat the incoming cycle, thus saving energy and effectively decreasing the amount of steam that blasts out upon opening.

Learn more about the benefits of steam elimination and energy recovery, as well as the key benefits of a standard vented or ventless dish machines in our article Vent vs. Ventless Dishwashers.

Door Type Dishwashers: Pros and Cons

Though space and throughput capacity (rated in racks per hour) are the most obvious considerations when upgrading from an undercounter to a door type unit, there are a few other pros and cons worth mentioning.

Additional Pros of Door Type Dish Machines:

  • Saves time and labor, allowing the user to clean more in a fraction of the time compared to their undercounter counterparts.
  • Enables longer, more efficient dry times due to the addition of dish tables.
  • Ergonomic, requiring minimal effort to insert and remove dish racks. Undercounter units require staff to bend over and lift cleaned racks. Not only can this cause physical strain when done repeatedly over time, but it can also increase the risk of breakage due to accidental drops.
  • Washes more ware per hour.
  • Better accommodates larger items.

A Few Cons to Consider:

  • Traditionally more expensive than undercounter units.
  • Takes up more space.
  • Uses more water per rack.
  • Need to factor door clearance. Average opening clearance is approximately 17”, but certain high hood machines feature a 25-26” door clearance to accommodate larger ware, such as sheet pans.

What About Conveyor Dishwashers?

The next step up from a door type unit is a conveyor dishwasher, designed for exceptionally high volumes. Conveyor units start at 44” wide and some restaurants opt for one because they boast a throughput capacity of more than 200 racks per hour.

Conveyor units and flight type machines, particularly those on the larger size, are traditionally reserved for institutions and high-volume cafeterias, such as those in universities. However, many buffet operations choose to install conveyor units, given the need to clean so many dishes in short amounts of time.

Tim Christianson, sales representative for HRI, Inc. representing Hobart, another industry-leading manufacturer of warewashing innovation, illustrates the primary benefit of considering a conveyor unit:

“A basic door-style machine will be rated for roughly 60 racks per hour, meaning it will take one minute to complete the washing and sanitizing function of one dish rack of ware. You then need to determine the amount of ware that will fit per rack. For simplicity’s sake, a dish rack will hold roughly ten trays – give or take a couple depending on size.


“If you have an elementary school with 400 kids and you have a total of 500 trays, you would have a total of 40 racks worth of trays to wash at the end of the day. That function, not including the physical loading and unloading of the racks, would take 40 minutes in a basic door-style machine.


“If you focus on throughput and realize that while the capacity of 60 racks per hour is sufficient for your needs, the 40 minutes required to wash that ware at the end of the day when it’s all piled up is not worth it. It would be a much better idea to move up to the smallest conveyor machine, which will automatically move the dish racks through the machine.


“Most of these machines start at 200 racks per hour and go up to 340+ racks. If we take the most basic at 200 racks per hour and apply that same capacity multiplier to the 40 racks of trays needing to be washed, that same amount of ware would be finished in 12 minutes instead of 40!”

Additional Dishwashing Considerations

Though the throughput capacity is one of the primary factors when selecting the right dish machine, Willoughby also pointed out some additional considerations.

Water Quality

“Water is the ultimate corrosive,” he says. “It will carve crevices through mountains. What do you think it’s doing to your dish machine?” It’s worth pointing out that this sentiment also applies to any equipment that relies on water, such as ice machines and steamers. “You look at giant skyscrapers, for example. Water is the number one factor relating to damage.

“In gist, the softer your water, the more effective your detergents and the less spotting you’re going to have on your glasses. The better your water, the better your wash.”

This is achieved by installing a water softener and ensuring your filters are changed regularly as part of ongoing maintenance. However, ensure you’re using the right filter that adheres to the psi of the unit (pounds of force per square inch), your machine’s flow rate, and the temperature of your water line.

High Temp vs. Low Temp

This refers to how your unit will sanitize your dishware after it’s cleaned. High-temperature dishwashers sanitize by raising the temperature to 180°F for the final rinse, hot enough to kill any bacteria. Low-temperature dishwashers use a chemical sanitizer to achieve this.

There are advantages and disadvantages to both. By and large, though, most commercial warewashing manufacturers recommend a high-temperature unit because they’re more effective in removing tough grease and substances, like lipstick on glassware. Dishes also dry faster in a high temp unit, and there’s no chemical residue that can distort the presentation and flavor of food and drinks.

Low-temperature units traditionally have a lower upfront cost, but they require the regular purchasing of sanitizing solutions. This cost can add up over time.

Cold Water Hookups

Some units advertise a cold-water-only hookup, which means operators will only need access to a cold water tap instead of both hot and cold. This saves on utility costs and construction expenses, making these units more flexible and ready to install in a range of locales.

Choosing the Right Dish Rack

Your dish racks will be your greatest ally in your dishwashing practices. It’s important to have the right type of rack for your ware. Dish racks keep your ware organized and contained throughout the wash cycle. Glass racks, for instance, come in a variety of configurations to support different glassware sizes and styles. If you wash your stemware in a rack designed for juice glasses, for example, you run the risk of your stems snapping off during the cycle. Racks for sheet pans and trays are also necessary to keep those slender, tall items upright through the cycle to guarantee thorough cleaning, sanitizing, and drying. 

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