Every commercial dishwasher gets a score from 0 to 100% built from seven factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Machines are grouped by type, undercounter, door-type and glasswasher, and use the same scale in every group.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per rack an hour of rated throughput | 30% |
| Throughput | rated racks per hour | 15% |
| Water use | gallons of water per rack | 20% |
| ENERGY STAR | ENERGY STAR certification | 10% |
| Door opening | tallest item the door or hood clears | 10% |
| Pumps | built-in chemical pumps and drain pump | 5% |
| Warranty | parts and labor warranty length | 10% |
Where the numbers come from
Racks per hour, water per rack, door opening, electrical ratings, pumps and warranty come from the maker’s spec sheet, product page or manual, and in a few cases from the maker’s own copy on a retail listing. ENERGY STAR status comes from the maker or the ENERGY STAR product finder. Prices are checked at the stores linked on each page, and the lowest price at a store the page links to is used.
The factors
Value is the current price divided by the rated racks per hour, on a log scale, so halving the price always counts the same. $400 per rack an hour scores zero and $100 full marks.
Throughput is the maker’s highest rated racks per hour on its fastest standard cycle: 20 racks an hour scores zero and 60 full marks. Some makers count load time and some don’t, so treat small differences with care.
Water use is gallons of water per rack as the maker publishes it: 1.5 gal scores zero and 0.5 gal full marks. Water is also hot water, so it is the largest running cost after labor and chemicals.
ENERGY STAR is full marks for a machine the maker or ENERGY STAR lists as certified, and zero otherwise.
Door opening is the tallest item the door or hood clears: 10 in scores zero and 20 in full marks. A taller opening takes sheet pans, stock pots and tall glassware.
Pumps is half for built-in chemical pumps (detergent and rinse aid, plus sanitizer on a low-temp machine) and half for a built-in drain pump, which lets a machine drain uphill to a wall or sink drain.
Warranty is the maker’s standard parts and labor warranty: 1 year scores zero and 3 years full marks.
What isn’t scored
Sanitizing type, voltage, amps and phase, booster and tank heater sizes, cycle time, wash tank size, rack size, dimensions, weight and release date are listed but not scored. A rotary glasswasher’s glasses per hour is shown but, with no racks-per-hour rating, its value and throughput factors score neutral.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. Pumps score neutral only when neither is published. Two factors are exceptions: a machine with no ENERGY STAR claim is scored as not certified, and a maker that doesn’t publish a warranty gets no warranty counted; both factors score zero and are marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.