Temperature Drop Calculator for Hydronic Piping

    This calculator estimates the temperature drop (or rise) of water flowing in a pipe.

    An example is the use of insulation to minimize temperature change (either temperature drop or rise) of a process fluid from one location to another (e.g., a hot fluid flowing down a pipe).

    Temperature Drop Calculator for Hydronic Piping
    Reference: ASHRAE 2009 HoF, Chapter 4, Equation 48 (page 4.21)


    Users will need to input the following:

    • Entering water temperature in °F
    • Ambient temperature in °F
    • Wind speed of ambient air
    • Flow rate of water, gallons per minute (gpm)
    • Length of pipe run in feet
    • Normal size of pipe in inches
    • Thickness of insulation in inches
    • Type of insulation material
    • Type of insulation jacketing


    Based on input, calculator will provide the following:

    • Temperature drop (or rise) in °F
    • Leaving water temperature in °F

    Release Notes

    The calculators are housed at the National Institute of Building Sciences' Whole Building Design Guide (WBDG) website under the Mechanical Insulation Design Guide (MIDG). Calculators can be used online without any specific software requirement, and you can print the results page for each calculation.

    For More Information

    For more information, use the comment page or contact the National Insulation Association help desk at niainfo@insulation.org or 703-464-6422.

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