1. Energy Prices: (default is weighted according to 0.75 commercial and 0.25 industrial tariffs). Demand charges are LBNL estimates. For sources, see: Estimated U.S. Electric Utility Average Revenue per Kilowatthour, Selected National Average Natural Gas Prices, 1999-2004
2. 24-hour operation is recommended or required (for safety reasons) in many circumstances. Part-time operation may be appropriate in some cases, e.g. educational settings with non-continuous occupancy.
3. Default value from Weale, J., P.H. Rumsey, D. Sartor, and L.E. Lee. 2002. "Laboratory Low-Pressure-Drop Design". ASHRAE Journal, vol. 44, no. 8, p. 38-42.
4. Electric reheat is not widespread, but incurs a large energy penalty where used (e.g. nearly twice the fume hood's direct fan energy use)
5. Weather data from Kjelgaard, J.M. 2001. Engineering Weather Data. McGraw-Hill. ISBN 0-07-137029-3
Hoods typically use 100% outside air; constant-volume system. In a constant-volume system air is reheated at each zone for temperature control. Humidification energy not included.
For more documentation, see: E. Mills and D. Sartor. 2003 Energy Use and Savings Potential for Laboratory Fume Hoods LBNL-55400.