Building Square Footage

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This seems like a silly question, but i would like some input regardless.
My building has three floors, each about 9,500 square feet. However, the
looking at the BEPU and other reports are showing a total utility cost of
110632$ and a $/sqft of 2.25. this shows a sqft of about 50,000 for the
building. Is this something that i should disregard or is it relevant? I
have also modeled the unconditioned space above each room as a separate
space. Could the program be combining this plenum space into the sqft of
the entire building? Is this plenum sqft affecting the output of the
reports? any help is greatly appreciated.

Rob Hudson

rdh4176's picture
Joined: 2011-02-14
Reputation: 0

Hi Rob,

this is a good question and important to understand about how inputs are
translated to DOE & reported in the output.

Yes you are right that the summary is accounting for the floor area of the
unconditioned spaces as well and the plenum spaces. If you look at report
LV-B, summary of spaces in your project you will find the info you are
looking for.

This report is a listing of all the spaces (or thermal zones) in the
project. Theis listing incudes both conditioned spaces as well as
unconditioned spaces and plenums. In reviewing this report, pay special
attention to the column labeled "space floor multiplier". The total area
and volume for each space is this value times the area and volume listed in
the last two columns. The building totals row includes the effect of these
multipliers, but the area includes plenums and unconditioned spaces as


Pasha Korber-Gonzalez's picture
Joined: 2011-09-30
Reputation: 600

Rob/ Pasha,

The kBtu/SF on the BEPS Report and $/SF on ES-D report use the conditioned floor area. Please see the LS-C report that shows the conditioned floor area you are modeling.

LV-B report does show all the spaces including unconditioned spaces and plenums, but the total area is not used in the summary report.

Without looking at your model, I can only make a guess that you might be modeling the Plenum zones as 'Conditioned'. By the numbers that you have provided:

9,500 SF x( 3 [floors] + 3 [plenums] ) = 57,000 SF subtract any unconditioned spaces and the answer would be ~ 50,000 SF

Please check your inputs for plenum zones under both 'Spaces' and 'Zones' and in both, the 'Zone Type' input should either be 'Unconditioned' or 'Plenum'.

Hope it helps.

Best regards,

Gaurav Mehta

Gaurav Mehta2's picture
Joined: 2011-09-30
Reputation: 0

That is the same logic i went through, and double checking my plenum zones
have shown that they in fact are all unconditioned or plenum. I can send
out the .inp file or the output reports if people have time to check it

rdh4176's picture
Joined: 2011-02-14
Reputation: 0

through careful inspection, i determined that the extra square footage was
being added not by the plenum spaces, but the "conditioned" dummy spaces i
had set up for my RTU and MUA units. problem solved.

rdh4176's picture
Joined: 2011-02-14
Reputation: 0