Water Heater Recovery Rate Calculator

The recovery rate is the amount of hot water the water heater is capable of producing in a given period of time.

Water heater recovery rate calculator.

A water heater s first hour rating fhr is the most important feature to consider when purchasing a new heater since it tells you how much hot water the heater can deliver in an hour of use. Various formulas for water heating calculations efficiency gph x 8 25 x temp. California flow rate guidelines of fixtures 5 for use in sizing storage and recovery rate requirement of the water heater can be reduced from 445 to 340 gph. Wattage of the heating elements burner size efficiency temperature rise required and the time frame used to measure the recovery rate.

Input specific heat btu output gph x 8 25 lbs gal. Rise x 1 0 btu hr. In an electric water heater if the wattage of the elements is 4500 the incoming water temperature is 40 degrees and you are heating the water to 120 degrees temperature rise of 80 degrees the recovery rate is 23 0 gph. Take a minute to calculate the amount of hot water your household needs on the busiest one hour period of time of any average day.

To properly size a storage water heater for your home including a heat pump water heater with a tank use the water heater s first hour rating. Rr hin μ dt ρ p 3413 btu kw dt ρ 3. Sizing storage and heat pump with tank water heaters. However it can be used to calculate general hot water recovery time for any amount of water.

The amount of hot water provided will depend on several things. The first hour rating is the number of gallons of hot water the heater can. The above calculator is for calculating hot water recovery time for hot water cylinders. Improving commercial kitchen hot water system performance characterized for its maximum hot water use to calculate the peak hot water demand.

Visit the solar water heaters page for more on these calculations.