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The Condensation Resistance Factor (CRF) Tool is intended to provide general guidance on suggesting a minimum CRF based on a project-specific set of environmental conditions.

While not an absolute value, the CRF is a rating number obtained under specified test conditions to allow a relative comparison of the condensation performance of the product. It will provide a comparative rating of similar products of the same configuration and permit the determination of the conditions beyond which an objectionable amount of condensation may occur.

Some interpretative allowances may need to be made in comparing products of dissimilar type or configuration (e.g. wall sections versus operating windows or versus fixed glazing). Condensation in the field can be a result of many variables. Thermal conductivity of surrounding building construction, interior/exterior trim, humidification control, and the method of heat distribution on the interior plane of the assembly will impact its overall performance. Conditions which may affect interior surface temperatures include (but are not necessarily limited to) the following:

  • Type of wall construction and material(s) used therein
  • For cavity walls, location of thermal barrier in the product with respect to the wall cavity
  • Closed drapes and/or shades
  • Depth of reveal (recess at stool, jambs, and head)
  • Positive exterior wind pressure or negative pressure within the building which may increase infiltration of cold air
    • Height of product above grade
    • Location of surrounding buildings and type of surrounding terrain
    • Wind velocity
  • Solar radiation and orientation
  • Water vapor pressure and temperature indoors
  • Water vapor pressure and temperature outdoors
  • Rate and amount of water vapor released to interior
The calculations used to determine the CRF rating are based on the procedures outlined in AAMA 1503-09, Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors and Glazed Wall Sections.

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This tool was developed and is maintained by representative members of AAMA as advisory information. AAMA DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS INFORMATION, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL AAMA BE LIABLE FOR ANY DAMAGES WHATSOEVER FROM THE USE, APPLICATION OR ADAPTATION OF MATERIALS PUBLISHED HEREIN. It is the sole responsibility of the user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content published herein.

How to obtain AAMA 1503
Click here to order AAMA 1503, Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors and Glazed Wall Sections.

User's Guide to Performing CRF Calculations
The User's Guide provides more information on how the CRF calculations are derived.

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