Undercounter Dishwasher Buyers' Guide

Compact Cleaning Machines

Finding the right undercounter dishwasher can help your foodservice business run smoothly. The two main types of dishwashers are divided based on how they sanitize dishes; high-temperature dishwashers use water heated to at least 180 degrees F to kill bacteria, while low-temperature dishwashers rely on chemical solutions to sanitize wares. Once you decide which will work best for you, you can continue narrowing down the field until you find the right fit for your business.

Sanitizing Method

The biggest step in choosing a dishwasher is deciding between high-temperature and chemical sanitization. High-temperature machines cost more up front due to the booster heater they require, but will usually recover that cost in the long run because they don't require constant chemical replenishment. Consider what you will be washing, as chemical sanitization uses bleach, iodine, or ammonia solutions that can damage some types of plastic and metal, and can etch glassware.

Maintenance also differs between the two. Low-temperature warewashers require chemical refills on a weekly or monthly basis, a cost that outweighs the purchase price of the machine over the life of most machines. High-temperature machines rely on a booster heater, which adds another major component that could potentially fail and require emergency service. Those units also use more energy, which can drive your utility bills up.


The efficiency of your dishwashing machine can be a major determining factor in how much it will cost you over its lifespan. As noted, high-temperature dishwashers typically use more power, so it is especially important to compare energy consumption between different models. Machines that have received certification from ENERGY STAR will be some of the most energy efficient on the market.

Water consumption will also vary by model, usually listed as gallons per wash cycle or gallons per hour. A big part of efficiency is how quickly the dishwasher can wash, usually rated in racks per hour. Being aware of how many dishes your business goes through in an hour can help you decide which dishwasher will meet your needs.


Many newer dish machines have digital controls, often with LED display screens, that manufacturers believe make them easier to use. Others have retained push-button designs, with typically fairly simple controls. Some dishwashers have an automatic start feature, starting the cycle as soon as the door is closed so that there is no need to worry about adjusting the controls with every load. Most modern dishwashing machines come with chemical pumps, since even high-temperature machines still need detergent and rinse aid. An indicator light or digital readout that lets you know those chemicals are low can make refills much easier to remember. When comparing models, be sure to note the chemical pump's and/or booster heater's location, and evaluate how it will fit into your setup.


Keeping your dishwashing machine clean is essential to prolonging its life and ensuring that it is operating as it should, so features that make the dishwasher easy to clean are very beneficial. Many machines feature easily removable wash/rinse arms and scrap baskets. Filters can help keep the debris that escapes the scrap basket from getting into other essential parts of the machine, and should be removable for cleaning as well. An easy-to-clean material, such as stainless steel, a lack of seams, and coved corners can be very advantageous when it comes to basic cleaning. For deeper cleaning, a delime cycle is needed to remove limescale buildup on the interior of the dishwasher.


Being aware of the utilities you have to work with can make shopping for a dishwasher much easier. Know the electrical capabilities of your space, such as whether your outlets are wired for one- or three-phase power, and how many amps the circuit can handle. While you are looking at the electrical requirements, make note of whether the dishwasher can just be plugged in or if it must be hardwired by a professional electrician.

If you are shopping for a high-temperature dishwasher, knowing the incoming water temperature is important; this will help you determine what type of booster heater you will need. When comparing booster heaters, note that the electrical requirements for the one you choose will be added onto the dishwasher’s, so you'll need to ensure the pair will not overload your circuit. Some booster heaters are powered by gas instead of electricity, in which case you will need a gas hookup placed near the dishwasher.


The intended location of the dishwasher can play a huge role in ruling out some of your options. For example, if you need the dishwasher to go behind a bar, it will be close enough to customers that it should not put out too much steam or make a lot of noise, so a low temperature warewasher or a high temperature dishwasher with good insulation may work best for you. Good insulation that keeps heat inside the machine is also important for the comfort of the operator if your dishwasher will be located in a small washroom. What you will be washing must also be considered; if you will be mostly washing glasses, you may want to consider a specialty glasswasher rather than a general dishwasher.


Neither chemicals nor extremely hot water should come in contact with skin, so safety features that prevent that are important to make note of. Most dishwashers feature a safety switch in the door that will stop the wash cycle as soon as the door is opened or prevent the door from opening when the machine is operating. This is especially important for high temperature dishwashers, as 180 degree F water will cause instant third-degree burns upon contact with skin. A large part of chemical safety is educating your operators and having a material safety data sheet nearby in case of a spill, but some machines have special trays or compartments to keep the chemicals in as an extra measure of safety.

Special Features

The competitive market in commercial dishwashers has led to manufacturers patenting a variety of special features to make their machines stand out. While some dishwashers have a set standard wash cycle, others may offer three or more time options so you can customize the cycle to meet your needs. These dishwashers sometimes have a manual override for longer wash cycles. Some units feature technology that monitors water temperature and will automatically extend the wash cycle until a sanitizing temperature has been reached.

Product protection is another available option, which gradually starts wash and rinse cycles to avoid jostling dishes and damaging them. Some features, such as low water and overheating detection, are instead intended to protect your dishwasher and prolong its life. Most companies also offer a warranty, a variable you may want to consider for additional peace of mind.