[Equest-users] Exterior insulation vs Exterior with Cavity insulation

[nic]

Sorry that I wasn't more clear, but I am questioning the major decrease in
energy performance between the baseline and the ALT 1 of 8%.  The U-value
difference is about 0.003, so I would expect a much smaller decrease around
0-0.5%.  THe problem I am having is with the exterior only application of
ALT 1 vs exterior and cavity fill insulation in the baseline.

ie. 90.1 Baseline is R13 fill + R7.5 continuous insulation
ALT 1 is R0 fill + R12 continuous insulation. (very common installation)

Thanks,
nic

On Wed, Jan 25, 2012 at 3:21 PM, Nikola Kravik <NKravik at willdan.com> wrote:

> I guess your “issue” or question relates to the amount of savings so
> you’re surprised how little savings you get increasing your wall insulation
> thickness?
>
>
>
> Don’t be surprised since you mentioned is internal load dominated plus
> there are other factors like climate, orientation and wall area that play a
> role so without the building description I don’t see any issue with the
> results you’re showing.
>
>
>
> Best,n
>
>
>
> Nikola Kravik, LEED AP [image: Description:
> cid:image001.gif at 01CB9AE0.30118F00]
> Project Engineer
>
> *Willdan Energy Solutions*
>
> 11875 Dublin Boulevard, Suite A-201
> Dublin, California 94568
> T. 925.556.2600 ext. 1228
>
> C. 925.719.5883
> F. 925.556.1444
>
> nkravik at willdan.com
> www.willdan.com/energy
>
>
>
> [image: WD_tagend_300rgb]
>
>
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *nic
> *Sent:* Wednesday, January 25, 2012 1:01 PM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] Exterior insulation vs Exterior with Cavity
> insulation
>
>
>
> 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.
>
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