Financial Calculator

    This calculator was developed to provide a convenient way to estimate the financial returns related to investments in mechanical insulation: Simple Payback in years, Internal Rate of Return (IRR or ROI), Net Present Value (NPV), and annual and cumulative Cash Flow. It can be used for an overall mechanical insulation project or for a small mechanical insulation investment such as insulating a valve or replacing a section of insulation.

    Mechanical Insulation Financial Calculator


    Users will need to input the following:

    • Initial cost of the investment in dollars
    • First year energy savings in dollars per year
    • Energy cost escalation rate as a percent per year
    • Estimated economic life in years
    • Discount rate as a percentage


    Based on input, calculator will provide the following:

    • Simple payback period in years
    • IRR or ROI as a percentage
    • NPV in dollars
    • Annual and cumulative cash flows

    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 or 703-464-6422.

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