Calculate water heater temperature rise, incoming water temperature, target hot water temperature, BTU demand, kW demand, tankless flow capacity, and hot water heating load for plumbing and water heater sizing.
Temperature rise:
The calculator subtracts incoming water temperature from target hot water temperature.
Target temperature:
The calculator adds known temperature rise to incoming water temperature.
BTU / kW demand:
The calculator estimates heating power needed from flow rate, temperature rise, and efficiency.
Flow capacity:
The calculator estimates how much flow a heater can support at the entered temperature rise.
A temperature rise calculator helps estimate how hard a water heater must work to heat incoming cold water to a target hot water temperature.
It can help compare incoming temperature, target temperature, temperature rise, required BTU/hr, required kW, flow capacity, and water heater sizing.
Your result shows estimated temperature rise and heating demand. This is useful for water heater sizing, tankless water heater GPM planning, recovery calculations, hot water demand estimates, and energy cost estimates.
Temperature rise is the difference between the incoming cold water temperature and the desired hot water temperature.
Tankless water heaters are rated by how many gallons per minute they can heat at a specific temperature rise. A higher rise usually means lower available GPM.
Subtract the incoming water temperature from the target hot water temperature.
No. This calculator gives a planning estimate. Actual water heating performance depends on heater efficiency, flow rate, fuel type, incoming water temperature, pipe losses, and manufacturer ratings.