Water Heater Recovery Rate

Most homeowners are simply unaware how important the "recovery rate" is when selecting a water heater. Recovery rate is defined as the number of gallons heated in 1 hour by 90°. In other words, if the incoming water is 50°, the recovery rate would equal how many gallons the appliance can heat to 140° (50°+90°) in 1 hour. Recovery rate and tank capacity are often very close in value for residential units (see photo & click to enlarge).

Tank capacity is somewhat misleading. I have inspected water heaters for 12 flats that are similar in size to a 50 or 75 gallon tank but the recovery rates are 200 gallons/hour! Many home owners believe bigger is better for this appliance and that is simply not true.

Tankless water heaters are coming but thats a completely different discussion. In the mean time, think "recovery rate" and a relatively small tank capacity.

Tank capacity is 38 gallons/hour (blue oval) and the recovery rate is 39.32 gallons/hour (red oval)