Indirect Water Heater Sizing Calculator

Size indirect boiler-fired water heaters based on recovery rate and storage capacity.

Peak hot water demand.
GPM
Duration of peak demand.
min
Temperature rise needed.
F
BTU available from boiler for DHW.
BTU/hr

Results

Peak Demand Volume-gal
Recovery Rate-GPH
Min Storage-gal
References: ASPE Data Book Vol. 4; ASHRAE HVAC Applications