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Why are the surface gross and net areas come back same.?

asked 2017-04-19 20:01:28 -0500

Karthick gravatar image

updated 2017-04-20 02:24:01 -0500

I have created my geometry and I have assigned materials for each of the surfaces. I have intersected and matched them. I am trying to get the properties of each surface and found that there are two methods for area. Gross and Net. They come back with the same value. I am unsure why have two methods that give back the same value.

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Please always tag your question with the specific software you're mentioning if appropriate (here openstudio). Thanks!

Julien Marrec gravatar imageJulien Marrec ( 2017-04-20 02:24:38 -0500 )edit

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answered 2017-04-20 02:22:55 -0500

They will yield different values if and only if you have subsurfaces on the surface, that is windows, doors, skylights, etc.

The surface.grossArea is the area of the surface itself. The surface.netArea is the surface.grossArea minus the surface of any subsurface. That's best explained with a little picture:

surface areas explained

So if here in the case of the left surface, there's a subsurface - a window - so they yield different results. On the right, there's no subsurface so they give the same value.

Note that surface.netArea will NOT calculate the thickness of walls or anything like this, there is no thickness in E+!

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Asked: 2017-04-19 20:01:28 -0500

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Last updated: Apr 20 '17