A restaurant owner once told me his dishwasher was "constantly breaking." After investigation, I found he'd bought a low-temp chemical sanitizing machine but was running it at temperatures that killed neither bacteria nor the chemicals he was using. He was essentially rinsing dishes with warm contaminated water. The machine worked fine—he just didn't understand what he'd bought.
High-Temp vs Low-Temp: The Fundamental Choice
High-Temperature Dishwashers
- Wash temperature: 150-165°F
- Rinse temperature: 180-195°F
- Sanitization: Heat-based, requires warewashing chemicals for final sanitizing rinse
- Best for: Operations with consistent hot water supply, most states accept high-temp certification
Low-Temperature Dishwashers
- Wash temperature: 120-140°F
- Rinse temperature: 120-140°F
- Sanitization: Chemical-based, requires approved sanitizing solution
- Best for: Operations where high temperatures might damage items, facilities without hot water capacity
The Real Differences That Matter
Operational Costs
High-temp machines use significantly more energy—heating water to 180°F versus 120°F costs roughly 40% more in natural gas. Low-temp machines require ongoing chemical purchases but typically use less water and energy. Calculate total cost of ownership over 5 years, not just purchase price.
Dish Damage
High temperatures can damage certain items over time—plastic containers, insulated mugs, some specialty items. If your operation includes delicate glassware or plastic items, factor this into your decision.
Machine Types
Door-Type (Single or Double)
The most common for mid-sized operations. You manually fill the machine, close the door, and the cycle runs. Typical throughput: 20-40 racks per hour for door-type machines.
Conveyor Machines
For high-volume operations. Dishes travel through on a conveyor belt. Can handle 100+ racks per hour depending on belt speed. Requires more space and water capacity but dramatically increases throughput.
Flight-Type
The beast of the industry. Continuous-flight machines for massive operations (1000+ covers). I rarely specify these for anything under 800 seats unless the operation is purely dish-intensive.
What to Look For
- Energy Star rating: Significant long-term savings
- Recovery time: How quickly it reheats between cycles
- Water consumption: Per-rack water usage varies significantly
- Built-in chemical dispensers: Saves money vs. manual adding
- Warranty and service support: Critical for minimizing downtime
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