[Equest-users] URGENT: Window U-values: Total window assembly v/s Glass only

Robby Oylear robbyoylear at gmail.com
Wed Jul 27 09:32:08 PDT 2011


Omar,

The answer depends on the purpose of your study.  If you're trying to get
results for a client on the impact of the glazing on their energy
performance, this may be adequate.  Make sure you've entered in the framing
information properly (metal vs. non-metal).

I'd recommend opening up your simulation output results file (xxxx.SIM) and
going to the either the last page of the LV-D report or sort through your
LV-E report to see what value eQUEST has calculated.  Compare these values
to the ASHRAE Fundamentals results for overall assembly values including
frame to see how close you've come.  I would not blindly trust that eQUEST
will give you an appropriate overall assembly value based on entering only
the center of glass number.

However, if this is for a LEED study, this is not adequate.  This an excerpt
from an e-mail I sent out recently regarding LEED and NFRC requirements.

In order to meet LEED EAp2 Minimum Energy Performance, the project must
comply with all mandatory provisions of ASHRAE 90.1-2007.  Section 5.4.2
Fenestration and Doors requires that fenestration performance be determined
per section 5.8.2.  Section 5.8.2.4 U-factor requires that the U-factor for
the overall fenestration area (including framing) be determined in
accordance with NFRC 100. If you do not have NFRC data available, values
from section A8.2 are the only acceptable alternative.

*Robby Oylear, LEED**®** AP BD+C*

*Mechanical Project Engineer*

*Energy Analyst*

* *

*D* 206-788-4571 | *C* 206-354-2721

*www.rushingco.com* <http://www.rushingco.com/>




On Wed, Jul 27, 2011 at 8:14 AM, Omar Katanani <omar at ecoconsulting.net>wrote:

>  Dear all,
>
>
>
> I have a small question regarding entering window properties to eQUEST:
>
>
>
> I have read a lot of emails in the forum discussing NFRC testing, LBNL
> Window 5 import, and other topics that I haven’t paid attention to before.
>
>
>
> The way I modelled my windows is the following:
>
>
>
>    1. I have manufacturer’s specifications listing the glass U-values, *
>    not* the total assembly.
>    2. In the “Glass Types” (eQUEST Detailed Mode), I created glass types,
>    and entered the *glass* conductance, visible transmittance, SC, and
>    emissivity from the manufacturer’s details I have.
>    3. When creating windows, I specify which glass type (from the ones I
>    created in step 2), in addition to the frame width and conductance.
>
>
>
> I’m assuming that, given that I entered the u-values for the glass only,
> and then I entered information about the frame, then I need not worry about
> any conversions in U-values, *since eQUEST has all the necessary
> information to calculate the equivalent u-value of the whole pane + frame
> assembly, *right?
>
>
>
> I appreciate your feedback / comments today if possible, as this has become
> really urgent!
>
>
>
> Many thanks,
>
> Omar
>
> ___________________________
>
> Omar Katanani
> Sustainable Design Engineer
>
> Email: omar at ecoconsulting.net
>
>
>
> EcoConsulting (Lebanon)
>
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>
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>
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>
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>
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>
>
>
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> Fax:  +44 (0) 207 939 0981
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