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

[Robby Oylear]

Omar,

To directly answer your question:

"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?"

No.  Your method will result in an assembly U-value based on your input
glass conductance and whatever default frame properties that the eQUEST
wizard will use.  I have never tried to let eQUEST determine an assembly
value, as NFRC values are required for LEED and code compliance studies.  I
would not be surprised if the values eQUEST is calculating (shown in LV-D
and LV-E reports like previously mentioned) are much different than what
you'll actually see in the test results.

Again, NFRC values are a LEED requirement, so unless you're just doing
preliminary analysis for a client, you need to receive NFRC simulation
reports or certified product directory numbers in accordance with NFRC 100.

*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 2:44 PM, <omar at ecoconsulting.net> wrote:

> Dear Robby,
>
> Yes, I am modeling for LEED purposes.
> I'll look into A8.2. But at least, is my method correct for the proposed
> scenario?
>
> Brad: I think you need to enter the center of glass u-value in the "Glass
> Type", and then enter the frame properties in the "Window" properties...
>
> Best,
> Omar
>
>
> Quoting Brad Robinson <brad.robinson at yahoo.com>:
>
>
>>
>> Is the u-value listed for a manufacturer and specific model on the NRCAN
>> website centre of glass or overall assembly?  Many windows are custom made
>> to suit so I am unclear if each individual custom window would need to be
>> tested.
>>
>>
>>
>> In eQuest, when entering the window, if the u-value represents the whole
>> window, including frame, do you need to enter a frame width, conductance etc
>> as well under the Window Frame section under Window Properties?  Thanks.
>>
>>
>> Brad Robinson
>>
>>
>>
>> ______________________________**__
>> From: Robby Oylear <robbyoylear at gmail.com>
>> To: Omar Katanani <omar at ecoconsulting.net>
>> Cc: equest-users at lists.**onebuilding.org<equest-users at lists.onebuilding.org>
>> Sent: Wednesday, July 27, 2011 12:32:08 PM
>> Subject: Re: [Equest-users] URGENT: Window U-values: Total window assembly
>> v/s Glass only
>>
>>
>> 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
>>
>> D206-788-4571 |C206-354-2721
>>
>> 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)
>>> NahasBuilding, 4th floor
>>>
>>> 4 St-Maron Street/ Georges Haddad Avenue
>>> Postal Code: 2028 5806
>>>
>> SAIFI
>>
>>> Beirut, Lebanon
>>> Tel:          +961 (0) 1 971 266
>>> Mobile:    +961 (0) 3 045 045
>>>
>>> EcoConsulting (UK) Ltd
>>> 28 Marshalsea Road
>>> London, SE1 1HF
>>> Tel:  +44 (0) 207 939 0989
>>> Fax:  +44 (0) 207 939 0981
>>> Website: www.ecoconsulting.net
>>>
>>>
>>>
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