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CLTD Roof & Wall Number

Welcome to Adicot, Inc.'s CLTD Roof and Wall Number Calculator, a powerful tool designed to simplify the calculation process for professionals in the building and construction industry. This calculator is specifically tailored to assist in determining roof and wall numbers, which are essential components in ASHRAE's CLTD (Cooling Load Temperature Difference) Cooling Load Calculation method. Users input parameters such as roof and wall construction materials and insulation levels, and the calculator will return the CLTD roof and wall numbers. These numbers are critical in evaluating heat transfer through the building envelope and are used as inputs in ASHRAE's CLTD method. Engineers and energy consultants can use this calculator for accurate cooling load for proper HVAC system selection and equipment sizing. The CLTD Roof and Wall Number Calculator by Adicot, Inc. empowers professionals in the building industry, streamlining the calculation process and enhancing accuracy. Its user-friendly interface makes this calculator a valuable asset for architects, engineers, energy consultants, and contractors. Stay ahead in the ever-evolving field of building performance and leverage the power of the CLTD Roof and Wall Number Calculator to optimize your projects and deliver exceptional results.


Review the methodology to ensure it aligns with your project's requirements.


  1. Enter the Roof Type

  2. Enter the Mass Location

  3. Enter the Insulation R-Value

  4. The CLTD Roof Number will be shown in the CLTD Roof Number box. 


  1. Enter the Wall Material

  2. Enter the Mass Location

  3. Enter the Secondary Wall Material

  4. Enter the Insulation R-Value

  5. The CLTD Wall Number will be shown in the CLTD Wwall Number box.


This calculator is based on the 1997 ASHRAE Handbook, Fundamental, Table 31, page 28.42 for Roofs and Tables 33A, 33B, and 33C for Walls.

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