Reference > Marc Rosenbaum's Writings

Understanding the Energy Modeling Process:
Simulation Literacy 101
from The Pittsburgh Papers (2003)

ACCURACY OF THE MODEL

Previous Page: GETTING, AND VETTING, THE OUTPUT

As the saying goes, the map is not the territory. No model will accurately predict the actual energy use of the building; there are too many variables to control.

• The building may not be built exactly as drawn, which can have an especially large effect on air leakage if that is a significant factor (as it can be in skin-dominated buildings).

• The occupants will use the building differently than predicted. They may use the building for more hours or use less equipment, for example.

• During extreme years, the climate may vary 20 to 30% from that modeled.

The value of the model is its ability to compare alternate schemes and show the resulting differences in energy use. The differences will tend to be more accurate than the absolute values. Don’t sweat the petty things (or was it don’t pet the sweaty things?).

Next Page: LIMITATIONS OF THE SOFTWARE

Page 5 of 6