How do I size a water heater for a commercial kitchen?
Add up the peak hot-water demand of your fixtures - three-compartment sinks, hand sinks, prep sinks, mop sink, and especially the dish machine - to get gallons per hour at peak, then size the heater's storage plus recovery to meet that peak hour. High-temp dish machines also need a dedicated booster heater to reach 180F final rinse. This tool estimates the peak GPH; a plumber sizes the unit to fixture demand and code temperatures.
What temperature does commercial kitchen hot water need to be?
Per the FDA Food Code, hand sinks need water capable of at least 100F, and manual hot-water sanitizing (3-comp sink) needs a 171F immersion rinse; high-temp dish machines need a ~180F final rinse (via a booster heater). Size the heater to deliver the right temperature AND the peak volume at once.
Do I need a booster heater?
If you run a high-temperature dish machine, almost always - it boosts incoming hot water to the ~180F final-rinse temperature the machine requires. Low-temperature (chemical-sanitizing) dish machines don't need a booster. Factor the booster separately from your main water heater.
Is this the exact water heater size?
No - it's a peak-demand estimate. Actual sizing uses fixture-unit demand, dish-machine GPH from the spec sheet, simultaneity, and recovery rate. A licensed plumber sizes the storage and recovery to your real peak.