# [Equest-users] Building Geometry

Cam Fitzgerald cam at energyopportunities.com
Fri Mar 13 05:27:31 PDT 2015

```Good morning, all,

The information provided regarding the modeling implications for this issue seem right, but the definitions in Section 3 are always a good place to find answers, although it tends to be a game of connect-the-dots.

In this case, Sections 9.5.1(b) and 9.6.1(b) both use the same terminology, gross floor area and Section 3 defines the gross floor area as being measured from the exterior faces of exterior walls. For interior walls, the area is measured to the center of the partition wall. Using the area from the interior face of the walls would actually underestimate the Baseline lighting power allowance in this instance. J

Have a great day!

Cam Fitzgerald

Energy Opportunities/a 7group company

From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Keith Swartz
Sent: Thursday, March 12, 2015 5:53 PM
To: Maria Elisa Rumeo
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Building Geometry

Maria,

The walls and other surfaces in the energy model are simple planes with no thickness. You can enter thicknesses of components like insulation, but the program just multiplies that thickness times the material R-value per inch as part of its calculation of the effective R-value (or U-value) of the assembly. The heat transfer calculation is in one direction perpendicular to the plane.

I often locate the exterior wall lines along the outside surface since gross square footage is usually based on the outside surfaces of the building.

For interior walls it would be ideal to go down the middle, but there is rarely anything to snap to and I don’t think it’s worth the time to create those points to snap to.  I often just pick a side, whichever happens to be most convenient. I also try to keep straight lines as long as possible, like picking an average location for a long corridor with a small jog in it.

Sincerely,

Keith Swartz, PE, BEMP, LEED AP

Senior Energy Engineer | Energy Center of Wisconsin | Madison.Chicago.Minneapolis

608.210.7123 |  <http://www.ecw.org/> www.ecw.org

From: Farid Pour [mailto:farid.pour at hok.com]
Sent: Thursday, March 12, 2015 1:12 PM
To: Maria Elisa Rumeo
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Building Geometry

As far as I know, it goes in.

From: Maria Elisa Rumeo [mailto:rumeomar at gmail.com]
Sent: Thursday, March 12, 2015 1:10 PM
To: Farid Pour
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Building Geometry

Hello,

It is a low-energy retrofit and the walls are really thick!

My fear is that by using the outside dimensions, then if the wall contruction goes 'outward' of these defined lines, then I am modelling a larger house ( the volume of the house in the model is greater than the actual volume) .

thanks,

maria

On Thu, Mar 12, 2015 at 2:05 PM, Farid Pour <farid.pour at hok.com> wrote:

It should not make that much of difference unless your walls are rally thick.   I suggest you trace the outside wall and then make sure of the wall thermal properties.

Farid

From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Maria Elisa Rumeo
Sent: Thursday, March 12, 2015 1:03 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Building Geometry

Hello,

I have an AutoCAD file of an old home that was retrofitted with thick (insulated walls). When I import this file and trace it to define the building footprint on eQuest,should I be tracing the OUTSIDE of the building (the brick face) or the INTERIOR of the building (the interior walls)? or should I draw a line in the middle of them and use that as my building footprint?

do you know the wall construction goes INWARD or OUTWARD from the building footprint you set?

thanks,

maria

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