If your building includes the use of purchased steam supplied to your HVAC system, the proposed (design) building is modeled as if the steam system is “located” in the building— with the same efficiency with which it typically operates. The designed build

If your building includes the use of purchased steam supplied to your HVAC system, the proposed (design) building is modeled as if the steam system is “located” in the building— with the same efficiency with which it typically operates. The designed building is allocated only the fuel cost (for natural gas or oil) required to generate and deliver the steam needed for the building.  The steam purchased is actually considered “free,” as steam rates are not included. And here is where your building really benefits—if the steam system also co-generates electricity along with steam, that electricity is assumed to be “free” to the proposed building, as well. (Refer to the latest guidelines from USGBC.)