A pyranometer was used to measure the direct total solar radiation falling on each elevation. The next step was to use a circle of black foam core on a stick to block the direct sun in order to measure the sky component of the diffuse solar radiation. The third step was to use a sheet of black foam core to block the ground reflected component of the diffuse solar radiation. These measurements were then entered into graphs with the (unmodified) Solar Heat Gain Factors for comparison.

The graphs show that the conditions in the field are approximately the same as the Solar Heat Gain Factors. There are several possible reasons why the numbers do not match exactly. The first is time of day. The actual time may not correspond with solar time. This is likely because all the measurements are shifted slightly from the SHGF line while closely following its curve. A second factor may be that the SHGF represents the solar radiation transmitted through the reference glazing, which reduces solar gains slightly. Therefore, measured numbers can be expected to be higher than the SHGF. Another factor could be the partly cloudy sky conditions that were prevalent on the day we took measurements. Also, measurements were performed with a hand held pyranometer. Slight shifts in the orientation of the sensor caused large fluctuations in the readings. It may have been more accurate to use a sensor mounted on a tripod, but that device was unavailable. Despite all these factors, the readings indicate that the Solar Heat Gain Factors are reasonable approximations for the solar radiation occurring on the site.