International Energy Conservation Code
Window U-Factors & SHGC Default Values
Instructions:
Review the methodology to make sure it aligns with your project's requirements.
Windows:
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Select Frame type
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Select the number of panes
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Select Clear or Tinted
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The U-Value, SHGC, and VT code default values will populate the results table.
Note: you can access NFRC's Certified Product Directory to search for your specific window's actual U-factors and SHGC values.
Doors:
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Enter the door type
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The code default U-factor value will populate the result box.
RELATED CALCULATORS:
Methodology:
NFRC U-Factor and SHGC values are critical when performing Cooling Load Calculations and Energy Code Compliance Calculations. Clients can often provide these values if the windows are new with their sticker still attached. As a side note, any window, door, or Skylight with an NFRC rating can be found using the NFRC's searchable database. In the event that the windows are existing or no longer have an NFRC label affixed, the International Energy Conservation Code (IECC) and Florida Energy Conservation Code (FECC) provide default values U-Factor, SHGC values, and VT values.
The values below are taken directly from the 2020 Florida Energy Conservation Code, Table C303.1.3(1) & (2), and the 2021 International Energy Conservation Code C303.1.3 (1) & (2) and show SHGC, U-Factor, and VT values for windows and doors:
TABLE C303.1.3(1)
DEFAULT GLAZED FENESTRATION U-FACTORS
TABLE C303.1.3(2)
DEFAULT OPAQUE DOOR U-FACTORS
TABLE C303.1.3(3)
DEFAULT WINDOW, GLASS DOOR AND SKYLIGHT SHGC AND VT
Example 1: You are performing a load calculation for an existing building. You do a site visit and see that the existing windows have metal frames and the single-pane glass has no tinting. What values should you use for the U-Factor, SHGC value, and VT value of the windows?
Find the U-Factor From Table C303.1.3(1) by looking up Metal Frame / Single Pane windows: U-Factor = 1.2
Find the SHGC and VT From Table C303.1.3(3) by looking up SINGLE GLAZED-Clear windows: SHGC = 0.8, VT = 0.6
Example 2: You are performing a load calculation for an existing building. You do a site visit and see that the existing doors are uninsulated and metal. What value should you use for the U-Factor?
Find the U-Factor From Table C303.1.3(2) by looking up Uninsulated Metal: U-Factor = 1.2
Example 3: Use Adicot's International Energy Conservation CodeWindow U-Factors & SHGC Default Values Calculator to solve the examples above:
