[Bldg-sim] Building envelope average energy demands

Nick Caton ncaton at smithboucher.com
Mon Aug 29 09:12:57 PDT 2011



I am pretty sure you will ultimately find yourself frustrated if you try
to find "typical" costs (construction or consumption) for specific
building elements - as you may have gathered, the reality of energy cost
breakdowns varies widely even within a specific building type - so
averaged percentages between projects, even if found, may not be of much
practical use.  


We can only speculate as to for whom you're asking and why, but I expect
you will find it much easier to cite/source construction and/or derive
consumption costs of a specific envelope for a specific building, which
you can then compare/contrast to the project you're actually discussing
to extrapolate expectations.  


Ideally, a perfectly similar building would make for an easy comparison,
but simply make a point to identify the major differences in the
referenced building's makeup/location/equipment/occupant usage so that
you can factor the data to "fit" the project under discussion, as









Smith & Boucher Engineers

25501 west valley parkway, suite 200

olathe, ks 66061

direct 913.344.0036

fax 913.345.0617



From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Giulio
Sent: Saturday, August 27, 2011 9:31 AM
To: Reba Schaber
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Building envelope average energy demands


I see. 
Do you dataset where I can I at least retrieve construction costs per
building components? Such as a breakdown of  Envelope/Energy Plant
Facilities/Plumbing/Elevators etc..?

Il 27/08/2011 04:41, Reba Schaber ha scritto: 

The graph/pie chart is not from ASHRAE 90.1.  I believe the author is
trying to show the energy savings of a building designed to the
requirements of ASHRAE 90.1 as compared to a building not following
energy savings design practices.


         Reba Schaber      Mechanical Engineer, P.E.
                                     LEED Accredited Professional
1660 N. Alvernon Way                Voice: (520) 731-2060
Tucson, Arizona 85712                Fax: (520) 731-2061
                        rschaber at phmech.com


From: bldg-sim-bounces at lists.onebuilding.org [
mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Giulio
Sent: Friday, August 26, 2011 2:17 PM
To: Goldwasser, David
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Building envelope average energy demands


Hi All,

thank you all for your quick response. Actually I don't want to
calculate that value, but just need to cite/reference a source that
gives information about this data. 

I found this http://www.sustainablefacility.com/articles/print/86593
where a graph is shown...but not really references fully. It says about
ASHRAE Std 90 - I dont have access to this. Is this a chart inside the
Do you know if it is inside the ASHRAE standards? 

In particular I'm looking at expenditure through external vertical
walls/windows - hence facades especially in office buildings.



Il 26/08/2011 23:06, Goldwasser, David ha scritto: 

Maybe not quite what you are looking for, but we have a video  tutorial
showing an envelope elimination parametric. In this example we used a
full service restaurant but you can do this with any model. The approach
is to run a baseline simulation and then to switch all exterior and
ground exposed surfaces to an adiabatic boundary condition. Next remove
all fenestration surfaces. Then re-run the model. Due to the load driven
nature of this project the maximum savings through envelope improvements
was just over 3%, but maybe would be 15-20% for an office. Of course it
depends where the project is located; the harsher the climate, the more
potential savings through envelope improvements. And it depends on the
quality of the envelope that you use as a starting point; building
activity, and mechanical system efficiency. 


Here is a link to the video.



And here is a link to COP adjusted end use graphs in Google Documents



This doesn't mean that only 3% of the energy is due to the envelope, but
it does show potential savings for retrofits on various elements. You
could get more specific and just isolate the roof, or even solar gain
from the windows. Or run create an elimination run for plug loads where
you set loads to nothing.





David Goldwasser, LEED AP

National Renewable Energy Laboratory




From: bldg-sim-bounces at lists.onebuilding.org [
mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of John Eurek
Sent: Friday, August 26, 2011 2:36 PM
To: Giulio Castorina; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Building envelope average energy demands


I don't know if this answers your question, but I have tried to
determine the % of energy use due to the envelope on a recent building
by running multiple energy models.  What I found was the energy balance
in complex.


An example is a perfect balance on a cold day 

"People" + "Lighting" + "Plug Loads" - "Loss through Wall" = 0


So if the insulation was higher, your loss though the wall would be less
and the A/C power usage would be increased.


You could hand calculate the envelope energy demand for an empty
unoccupied building, but with internal loads it gets foggy.


The energy model will show you what you can expect from various
R-values, but I have not found a way to say x% of energy is due to the


From: Giulio Castorina <artitecture at gmail.com>
<mailto:artitecture at gmail.com> 
To: bldg-sim at lists.onebuilding.org
Sent: Friday, August 26, 2011 2:52 PM
Subject: [Bldg-sim] Building envelope average energy demands

Hi All,

Can anyone advise a good resource (article, webpage, book, etc..) which
states what is the average energy demands (construction+running costs)
due to Envelopes only in buildings? I would need just a figure in
percentage over the whole energy demands of a typical office building.
Is this data somehow available?


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