The purpose of this research was to compare the daylightingand building energy prediction from DOE-2.1E withmeasured quantities from an actual building. Weather informationtaken at the site was used to create weather files for thesimulations. Input files were created to model the test conditions,and model results were compared to room-level energyand lighting values.

For these tests, a diffuse window treatment was applied onthe interior side of the double clear-glazed windows. On average,DOE-2.1E predictions for the electric lighting powermatched the measured light power within 19.8%. Illuminancepredictions at the reference point were generally very close tothe measurements, except when relatively diffuse daylightentered the space; then the illuminance was overpredicted.Overall, the illuminance predictions were within 16.8% forexperiments. The zone airflow rates were also comparedduring the tests. The predictions for the airflow rate werewithin 3.0% for the test.