My energy model is about done but of course I am now questioning myself somewhat.  My questions are as follows and I could really use some help!  This forum has been a great learning tool.

1. I have a baseline system type 3 with a baseline of 8 single zone systems, does each single zone system need its own heating/cooling plant? I have multiple thermal zones in each single zone system, but all the single zone systems are served by one plant.  This would increase my plants from 1 to 8, since I have 8 single zone systems in the baseline.

2. How do I properly model a mechanical room exhaust fan which turns on when room temp is above 85F?

3. Is there a way to model an instantaneous gas fired water heater?  It appears that modeling a water heater as a base utility would not show any energy savings as this models a heater as constantly heating the water vs instantaneously heating it when needed.

Thanks in advance for the help! ~Amy