Exterior insulation vs Exterior with Cavity insulation

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I am attempting to establish a few alternatives compared to an ASHRAE 90.1
Wall construction. This much seems pretty straightforward with the only
change between alternatives being a different construction applied to the
exterior above grade walls. All alternatives are modeled as delayed and
with layered materials. The wall from outside to inside is stucco(finish)
R0.08 + Cont. Insulation R-VARIES + Ext sheathing R0.56 +
Framing/Insulation R-VARIES* + Int. Sheating R0.56 (air films do not
change, infiltration does not change, etc.)

*framing 16" Mtl OC taken into account

<<< I should mention the building is very much internal load dominant as an
education building with a lot of laboratory space >>>

The problem described below has been input into eQuest using material
properties for all continuous insulation and a representative R-value for
framing/insulation.

BASELINE - 90.1 - R6* + 7.5 ci na

ALT1 - only ext insulation R0.9 + 12 ci -8% savings (% energy under EUI -
kBtu/sf/yr)

ALT2 - improved ext insulation R6* + 12 ci +1% savings

ALT3 - improved cavity insulation R7.1* + 7.5 ci +1% savings

ALT4 - all insulation improved R7.1* + 12 ci +2% savings

I guess the question really is; does the issue lie within the vav systems
or the envelope or both?

As a novice, I greatly appreciate any help.

Nicholas Fonner
Energy Modeling Group
Henneman Engineering, Inc. | energy. focused.
1605 South State Street, Champaign, IL 61820
V 217.359.1514 | F 217.359.9354 | C
www.henneman.com | nfonner@henneman.com

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