How to Choose the Right Commercial Dishwasher

Washing dishes by hand, in a three-compartment sink, is a slow and labor-intensive process. Additionally, it is difficult to control important factors such as water temperature, chemical concentration, and immersion time. Unclean dishes create a bad impression and can be unsafe. Commercial dishwashers eliminate the need to wash dishes manually. They provide more reliable cleaning and sanitizing in less time with much less labor. Size, price, and configuration vary dramatically, and your choice will depend on the availability of space, your hot water supply, menu, and the volume of dishes to be washed. There are a wide variety of types and configurations available for all applications including specialty units.

Initial Considerations

A preliminary step when selecting a commercial dishwasher is to evaluate some key factors in your foodservice operation:

Available Space – Common dish room equipment includes a commercial dishwasher, pot sink, drain boards, and drying racks. Consultants generally recommend about 5 square feet of dish room space for every seat in the front-of-the-house. A 100-seat dining room needs about 500 square feet of space (e.g., a room of about 20’x25’). If you are short on space, you may have fewer choices.

Electrical Service – Dishwashers commonly require either 120V or 208V service depending on the type. While any licensed electrician can install the service you need, installation is an initial cost that should be factored into your buying decision. Additionally, check the utility rates in your area. Electricity costs may have an impact on your buying decision.

Hot Water – Determine whether your facility has a constant supply of sufficiently hot water. Additionally, check the water rates in your area. In drought prone areas, water utility costs can be high. The availability and cost of hot water can be a factor when deciding what kind of dishwasher to purchase. Gas or electric booster heaters and holding tanks can be added to provide optimal temperature and water flow, but the additional expense must be considered.

Menu – How soiled are your dishes? Are you washing light soil from a menu that features soups, salads, sandwiches, and lighter fare? Or are you washing heavy soil from a menu that features a large amount of melted cheese, fatty meats, fried foods, and/or melted sugar. Some types of dishwashers are better suited for heavily soiled dishes.

Capacity – How many racks of dishes per hour do you need to process? Multiply the number of meals served per hour times the average number of dishes per meal. That will tell you how many dishes per hour you need to wash. Divide that by 20 to determine racks per hour.

High Temp vs. Low Temp

Commercial dish machines must be able to wash, rinse, and sanitize. High temperature dishwashers rely on hot water (180° to 195°F) to sanitize. Most of them filter and reuse the wash water after each cycle to minimize water use. This also speeds the cleaning process because the machine doesn’t pause to refill. In contrast, low temperature dishwashers rely on chlorine-based chemicals to sanitize. They operate with water temperatures as low as 120°F. Most low temp machine dump and refill the wash water after each cycle, and then add more cleaning agents and chemicals. Low temperature machines use more water and chemicals but require less electricity to heat the water.

Up-front costs commonly influence the decision between high and low temp dishwashers. For operators with plenty of startup capital, a high temperature dishwasher is more expensive to purchase, but will provide the most effective cleaning with more long-term savings. For operators who lack startup capital, a low temperature dishwasher is usually less expensive to purchase. Additionally, many chemical companies “lease” or rent low temp machines at reasonable rates in exchange for lucrative chemical contracts. Over time, operators will spend much more on chemicals and monthly payments, but they can get up and running with a minimal outlay of cash.

Advantages of High Temp Dishwashers

  • No need to purchase chemical sanitizers
  • Dishes dry more quickly so they can be put back into service faster
  • Wash water is filtered and recycled resulting in 50% less water use
  • Recycling wash water results in faster cycles and more racks per hour
  • High temperatures are more effective at removing:
    • Lipstick from glassware
    • Greasy residue from foods like fried chicken, grilled meats, bacon, and pizza
    • Melted sugar from bar glasses and dessert dishes
    • Baked-on proteins like eggs and cheese
  • No chemical residue to affect the taste of fine beverages and delicate foods
  • No chlorine sanitizer to damage or discolor plastic or metal cookware, flatware, or serving ware

Disadvantages of High Temp Dishmachines

  • Require an onboard or exterior booster heater to raise hot tap water to 180°F
  • Use more electricity than low temp machines
  • Most require 208V electrical service (check specifications)
  • Initial purchase price is typically higher than low temperature machines
  • Usually require a Type II hood for removal of heat and steam


Advantages of Low Temp Dishmachines

  • Typically use hot tap water straight out of the facility’s main hot water supply
  • Require less energy to heat water
  • Most operate on a 120V circuit
  • Initial purchase price is typically lower than high temp machines
  • Can be leased from chemical companies in exchange for chemical purchasing contracts
  • Generate less steam and water vapor; usually do not require a hood

Disadvantages of Low Temp Dishmachines

  • The purchase of chemical cleaners and sanitizing agents is an ongoing expense
  • Clean dishes take more time to dry
  • Refilling the wash tank after each cycle slows the cleaning process
  • They use up to 50% more water
  • Low temperatures are less effective at removing:
    • Lipstick from glassware
    • Greasy residue from foods like fried chicken, grilled meats, bacon, and pizza
    • Melted sugar from bar glasses and dessert dishes
    • Baked-on proteins like eggs and cheese
  • Chemicals can affect the flavor of some beverages and delicate foods
  • Chemical sanitizers can damage or discolor some plastic and metal cookware, flatware, and serving ware

Manufacturers such as Champion, CMA Dishmachines, Hobart, Jackson, and Moyer Diebel all offer a variety of high and low temp models.

Types of Dishwashers

Undercounter & Underbar – Undercounter dishwashers may look very similar to the consumer models found in many homes, but they are more powerful and designed for the rigors of commercial use. Most feature a door that tilts open from the front. They rely on standard commercial dish racks that are loaded in and out of the machine manually. They are ideal for small operations like coffee shops and kiosks. They are also ideal under the bar. They eliminate the need to wash dishes by hand and minimize the need for bartenders to transport glassware to and from the kitchen for washing. Available in both high and low temp models, high temp underbar machines often feature a heat reclamation system to keep steam and water vapor from escaping into the customer area when the door is opened. They can typically do about 30 racks per hour. Manufacturers such as Champion, CMA Dishmachines, Hobart, Jackson, and Moyer Diebel offer undercounter models.

Door Rack / Type – If you need more capacity, but don’t have a lot of extra floor space to work with, then a Door / Rack Type dishwasher is often the best choice. They are better for medium sized operations. Most are designed to process a single rack of dishes at a time. Instead of tilting out, the doors lift up and out of the way. Many can be loaded from either the front or the side and they can be placed between two dish tables or in a corner. Due to the additional vertical dimension, door / rack type dishwashers can often accommodate larger stock pots and sheet pans that wouldn’t fit in an undercounter. Available in high temp or low temp models, they typically process 30 to 60 racks per hour. Manufacturers such as Champion, CMA Dishmachines, Hobart, Jackson, and Moyer Diebel offer door /rack type dishwashers.

Rack Conveyors – Rack conveyors have a larger footprint and are for high volume dishwashing. They are good for large restaurants, cafeterias, and other high-volume venues. Installed between two dish tables, the wash chamber features a conveyor belt with strip doors on both ends. When a rack of dishes is slid a few inches into the machine, it triggers the wash pump and engages the conveyor belt. The conveyor carries the racks through the machine. They emerge from the other end, washed, rinsed, and sanitized. Rack conveyor machines are available with single or multiple tanks. In general, the more tanks, the faster the machine can process and clean dishes. Most rack conveyors are high temp machines, but low temp models are available. They can process between 200 and 350 racks per hour. Manufacturers such as Champion, CMA Dishmachines, Hobart, Jackson, and Moyer Diebel offer rack conveyors.

Flight Type Machines – Flight type machines have a very large footprint and are for large hotels, casinos, universities, and other high volume operations that have a constant flow of dirty dishes. They feature a continuously advancing conveyor belt. They do not use dishracks. Instead, the conveyor surface features vertical pegs that allow operators to load dishware, glassware, and cooking ware directly onto the conveyor belt (flat racks or baskets are used for silverware and other small utensils). To keep the conveyor moving, clean dishes must be removed from the belt or it will pause until they are. Flight type machines commonly include a blower system to dry dishes after the rinse cycle. Conveyor belts range from 21 to 60 inches wide and the wider the belt, the higher the capacity. Smaller units can easily double the output of a rack conveyor, and larger units can process up to 24,000 dishes per hour, the equivalent of 1,200 racks per hour. Manufacturers such as Champion, Hobart, and Jackson offer flight type dishwashers.


Energy and Water Efficiency

Energy Star certified dishwashers are about 40% more energy efficient (and 50% more water efficient) than standard models. Eligible products include both high and low temperature stationary rack machines and conveyor type machines. According to Energy Star, a qualifying dishwasher can save operators an average of about $1500 annually, or about $19,000 over the life of the dishwasher. Manufacturers such as Champion, CMA Dishmachines, Hobart, and Jackson offer Energy Star rated models.

Some modern dishwashers feature heat reclamation systems. These systems capture heat exhaust and reuse it to maintain wash temperatures. They also eliminate the need for a Type II hood to remove steam and heat. Further, some modern dishwashers feature insulated wash chambers to retain heat and keep exterior surfaces cool to the touch.


Specialty Machines

Glasswashers Typically for underbar use, glasswashers feature an open front with strip curtains and a slowly rotating platform or carousel. Glasses placed on the platform are carried through the strip curtains into the rear of the machine where they are washed, rinsed, and sanitized. When they reemerge on the other side, they are clean. Carousel type glass washers eliminate the need for racks and can provide a continuous supply of 800 to 1,400 glasses per hour. Manufacturers such as Champion, CMA Dishmachines, and Jackson offer carousel type glass washers.

Bakery and Pot Dishwashers – Similar to door / rack type machines, they are sized to hold large numbers of full sized sheet pans standing on end. Usually, pans are loaded from the front into a stationary rack. The door is lowered to start the wash cycle. They are for bakeries and operations that need to process large numbers of dirty sheet pans. Similar units are available for washing large stock pots and items that are too tall to fit into a standard dishwasher.



Each operation has its own unique dishwashing needs and challenges. Manufacturers such as Champion, CMA Dishmachines, Hobart, Jackson, and Moyer Diebel offer a wide variety of dishwashers that can solve many problems such as utility costs, space limitations, capacity demands, and budget. A Kitchen Spot expert can help you evaluate your operational needs and provide advice about all the various models and features to choose from.