Water Heater Sizing Formula

After sizing a tankless water heater and evaluating your needs it may become clear that a tankless water.

Water heater sizing formula.

Knowing your family s first hour water usage will help you get the right size heater. Input specific heat btu output gph x 8 25 lbs gal. The formula goes like this. While tankless water heaters do not run out of hot water if not sized correctly the flow rate of that water can be adversely impacted.

To select the right state water heater for your home try our xpert product selector for personalized estimates of the performance and estimated energy cost. H out q ρ dt c p 1 where. Sizing storage and heat pump with tank water heaters. Once you have your total flow rate and the required temperature rise you can find the right size tankless water heater for your home.

Water heater sizing heating water is the second biggest energy expense in your home. Btu is a measure of how much energy is needed to heat water. Then evaluate tank water heaters on the same gph basis to determine how many gallons of storage are needed to meet this demand. Output heating capacity of a domestic hot water system.

Sizing tank water heaters. Getting a heater that is too small will create havoc in your household but getting a heater that is too big will cause you to waste money on the initial purchase and costs to. Various formulas for water heating calculations efficiency gph x 8 25 x temp. 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.

Rise x 1 0 btu hr. The higher the btu the more water it is capable of heating. H out heating capacity output btu h q flow rate gph ρ 8 34 density of water lbs gal dt temperature rise o f c p 1 0 specific heat of water btu lb o f input heating capacity. Pro size is intended to assist in selecting water heaters or boilers that best meet the specific job requirements.

Smith pro size sizing program is a tool that can be used to estimate water heater requirements for many common applications. Establish peak demand measured in gallons per hour gph. 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. Below we ve highlighted what size water heater you would need in our example of 6 5 gpm at a 63 f temperature rise.

Rise x 1 0 btu input gph x 8 25 x temp. Simply locate the appropriate water heater sizes on ecomfort using your information.