The first hour rating is the number of gallons of hot water the heater can supply per hour starting with a tank full of hot water.
Hot water tank sizes and capacity.
1 or 2.
You can estimate the necessary tank capacity in gallons based on the number of people in the house.
It depends on the tank capacity source of heat burner or element and the size of the burner or element.
If your family size is 5 or more you ll need an 80 gallon tank electric or a 50 gallon tank natural gas or liquid propane.
We recommend sizing the cylinder depending on the number of bedrooms bathrooms and showers.
For a tank style heater household size is a simple indicator of hot water needs.
This tank size based on the scenario in step 2 is adequate for the peak hourly hot water.
Choose a hot water heater with a tank size in the range of 50 to 60 gallons on the fhr label.
Storage tank hot water heaters are sized based on btu input and capacity in gallons.
Specifying the size of domestic hot water cylinders and tanks is a little easier to determine as the demand tends to be more predictable.
Split systems which store the hot water in an external tank are generally favoured over thermosiphon systems for households with a bigger demand for hot water.