A tool used to estimate the flow rate, measured in gallons per minute (GPM), required for a tankless water heater to adequately meet the hot water demands of a household. For example, a residence might need to run a shower (2.5 GPM) and a kitchen faucet (1.5 GPM) simultaneously; this scenario would necessitate a unit capable of providing at least 4 GPM.
Determining the correct flow rate is crucial for ensuring user satisfaction with a tankless water heating system. Underestimating the flow rate may result in inadequate hot water supply when multiple fixtures are in use, while overestimating may lead to unnecessary expense. Historically, estimations relied on manual calculations or rules of thumb; these tools provide a more accurate and convenient means of assessing hot water requirements.
