Deriving energy use by subtraction is a viable method for metering by end use.Remember that “HVAC" is not an energy end use, as it usually includes space heating, space cooling, fans, pumps, etc. which are the end uses. The credit allows the grouping of packaged units serving similar occupancies and schedules. The key to cost effective metering starts with organizing the panel boards by energy end uses. Trying to create the necessary meters within mixed boards can be very difficult and expensive.
We are proposing to metering a new building with a single controller. The controller has the capability to monitor each individual end use (lighting, plug loads, HVAC, water, gas, etc.). Can we meter everything on a distribution board except one specific end-use, such as HVAC, and have the controller programmed to calculate the difference in the main power usage and all the metering loads to determine the remaining loads (HVAC loads) and still obtain the advanced energy metering credit?