Commercial Water Heater Manuals & Owner Guides

Commercial water heater types

Gas storage

A tank with a gas burner sized for the building's peak demand. Condensing models reach thermal efficiencies of about 94–99%.

Gas tankless

Heats water on demand as it flows; capacity is measured in gallons per minute. Often installed in multiples for large loads.

Storage-type instantaneous

High-input units with a relatively small tank that recover very quickly — useful where demand comes in large, short bursts.

Heat pump

Moves heat from air or water into the tank instead of generating it, delivering several units of heat per unit of electricity.

Thermal efficiency, standby loss and COP

Thermal efficiency (TE) is the share of the fuel's energy transferred to the water at full fire. Standby loss (Btu/h) measures heat lost from a storage tank while it holds temperature. Heat pumps are rated by coefficient of performance (COP): a COP of 4 means four units of heat per unit of electricity.

Temperature, scalding and Legionella

Many facilities store hot water at 140 °F (60 °C) or higher to limit Legionella growth, then temper it with thermostatic mixing valves before it reaches fixtures. Follow your facility's water-management plan and local health codes.

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