What to look for and measure in the field

Window measurements can be noted on a floorplan so you can note which windows have the same measurements and use your time efficiently. In your analysis, you can use this data to calculate the window to floor area ratio. The window area shouldn't exceed 15% of the floor area, and if it does the heat gain could be large and the resulting energy use could be high (check the data if you have it). 

Noting the manufacturer and type of glass in the windows is important information you may need in your analysis. A couple of places you can find the manufacturer is on the hardware (locks or handles), between the glass, or on the window casing.  A glass code can be found on a corner of the glass and is typically an etched string of letters and numbers. This code can help you look up the model of the window and more information when you're back in the office. For more information on how to look for information on a window, check out this article. 

You will use the information you gather in the field to determine the U-factor and the Solar Heat Gain Coefficient (SHGC) for the windows in the building. SHGC is a measurement of how much heat from solar radiation is transferred into the building, or how well the window blocks the heat from sunlight (a lower value means less heat gain through the window).