I have done my best to read through the BLDG-SIM archive as well as AppG
and the LEED CIRs. I know this topic has been covered extensively but
for my own piece of mind I need the advice of the group.

I have a building that half the floors HVAC are being renovated, half
are to remain as is. Building shell is untouched, but a safety over
cladding is being added to the exterior. Plant is new chillers and old
boiler to remain.

Here is my interpretation from 90.1, LEED NC2.2 and CIRs from 20081210 &
20090209, and is assumed that the whole building must be modeled since
all areas feed of the same building central plant.

Envelope

Baseline = existing envelope

Proposed = existing envelope w/ benefit of over cladding

Lighting

Baseline = Table 9.6.1 based on space classification

Proposed= Renovated lighting levels where new + non-renovated levels
where existing to remain

HVAC

Baseline = Renovated areas Table G3.1.1B + non-renovated areas existing
old HVAC design

Proposed = Renovated areas New HVAC design + non-renovated areas
existing old HVAC design

(which would also mean old boiler in both cases, new chiller[proposed]
vs prescriptive[baseline] req't)

Receptacles

Same in Both (mix of old and new levels)

My concern is in the lighting levels. It would seem based on the CIR
from 20090209 that if untouched HVAC gets to be modeled the same in
both, then lighting should as well but I didn't see that mentioned
anywhere. Of course if I have this completely wrong I would like to know
that as well but this is what I gathered thus far. Any help would be
appreciated.

Thanks

Alan Jackson, LEED AP