Article #1496 - COMcheck Web-Based Training Questions - Windows

This article contains questions asked during the August 18, 2005 live broadcast of the COMcheck Web-Based Training session. The original language of the questions and answers has been modified to make them as generic as possible while retaining the applicable specific information.

When inputting window sizes, is there a way to account for variations in window frame thicknesses? (i.e. a 2" wide frame versus a 4" wide frame)

Window dimensions are taken as the outside of the frame.

How do you get to the default table?

In the input cell for U-factor right click with your mouse and select "Use Default" from the drop down menu. This automatically inputs the program default for the window you have already defined on that line.

Do the default values represent the maximum allowable values for each component?

The default values are simply an estimate of what the typical (but close to worst case) value might be. It is strongly recommended that you get the actual value.

What is glazing exactly?

Glazing is any translucent or transparent material in exterior openings of buildings, including windows, skylights, sliding doors, the glass area of opaque doors, and glass block.

Are window areas added to wall areas or subtracted out?

Wall inputs should should be gross wall area including the square footage of all windows and doors. The calculated window-to-wall ratio (% of glazing) will be displayed on the Envelope Compliance Certificate.

Will the trade-off capability of the COMcheck program still allow buildings with an extreme amount of glass? (greater than 65%) What is the realistic upper limit?

Compliance to the IECC in COMcheck is allowed for buildings where the window and glazed door area is not greater than 50% of the gross area of the above grade walls. Buildings with more glazing will need to meet the applicable provisions of ASHRAE 90.1. COMcheck can be used to show compliance to 90.1.