Hi everyone!  

    I am learning TREAT, so perhaps this is too simple of a question for you guys but I am kind of stuck... when TREAT asked me about the building I choose attached, considering that one wall of the building is attached to the neighbor's house, but when I check walls, all of them are set up to the outside, and so far I have not found the way to change the setting for that attached wall. Just for me to learn, is that attached wall considered towards living space? -considering that there is a firewall separating both units. 

   Your help is greatly appreciated!

                                    Luis

Views: 148

Replies to This Discussion

Hi Luis,

This is a great question that points to a fundamental tenet of energy modeling: we don't worry about surfaces (walls, floors, etc.) where there's no energy transfer.  We assume that temperatures between adjacent units (or between conditioned bedrooms) are essentially the same, so UA∂T = 0 (the delta-T is zero), and there's no point in modeling the boundaries between them.

In other words, don't model walls between adjacent units, floors over conditioned spaces, ceilings under adjacent units, etc.  You've already discovered that TREAT doesn't give you the option to specify conditioned space adjacency. 

So, unlike detached single-family homes, that will have at minimum 4 walls, a floor, and a ceiling, attached units will often have fewer.  The most "minimal" case is an inside apartment unit on a middle floor, which might have only one surface, a wall, on the Walls/Surfaces screen.

I hope this helps clarify.  Remember, energy modeling is not the same as architectural modeling -- we don't need to worry about surfaces that are there for structural or aesthetic reasons, but that have no thermal transfer.

 - Ethan

Thanks for reply Ethan,  

    Just curious, exterior walls have negative energy transfer (energy loss), heat gain from sun exposure, wind, etc, so when modeled as adjacent to the outside, with the R value of all materials, there is a calculation of that lost energy. I am thinking that the firewall should be pretty energy neutral and so I was thinking it should be represented as wall adjacent to condition space; even though I understand that walls from inside the condition space are not modeled. But the other Townhouse is not part of this condition space....  maybe I am seeing this the wrong way...  hmmm, love building science!

              Luis

Exactly right, Luis.

The other unit is conditioned also, so there's negligible energy transfer between them, so the common walls don't provide a heating or cooling load, and there's no reason to enter them in the model.

And to simplify it, there's no way to enter them in TREAT.

If you created this model with the New Building Wizard, you probably have at least one wall that you just need to delete from the model -- the one that would have been adjacent to the other unit.

 - Ethan

Great Ethan!  

I am going to give it a try!!! I know that what you say makes sense... it just feel silly modeling 3 walls

I really appreciate your comments!

                      Luis 

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Jim Gunshinan posted blog posts
16 hours ago
H.O. Electric posted a photo

about us-team

H.O. Services is your residential Electric-Plumbing-Heating-Cooling Specialist. We are an…
16 hours ago
H.O. Electric added a discussion to the group News & Announcements
Thumbnail

Stay Cool With Easy To Install Ductless AC System!

Stay Cool With Easy To Install Ductless AC System!   Save $300.00 Off A New AC System For A Limited…See More
16 hours ago
Richard Wells commented on Diane Chojnowski's group Facebook Pages
"Three thousand home energy efficiency audits, and nearly a thousand retrofits in four short…"
18 hours ago
Richard Wells joined Diane Chojnowski's group
Thumbnail

Facebook Pages

Does your company or organization have a Facebook Page?This group is for pros who have facebook…See More
18 hours ago
David Baerg replied to Blake Shurtz's discussion Air sealing wood-burning fireplace from the crawlspace below
"Hi Blake, Do you mean around the underside of the hearth?  Are you trying to seal between the…"
18 hours ago
Tom White's video was featured

Rebirth Realty: Restoring Detroit properties for Venture for America Fellows

Its been a long, cold winter, but we've made significant progress in the restoration of 760 Virginia Park. Join Tim Dingman on a walkthrough to see what we've done.
20 hours ago
Kim Tanner added a discussion to the group Multifamily Buildings
Thumbnail

Blower Door Applications Guide

TEC and Camroden Associates have released their big building testing manual, Blower Door…See More
20 hours ago
Profile Iconmichael coleman, Dan Liska and Rob Moreno joined Home Energy Pros
20 hours ago
Christopher Morin's blog post was featured

5 Things New Energy Efficiency HVAC Contractors Need to Know

1. Do not sell on Price! Use 'Simple Payback'The price of High-efficient equipment will undoubtedly…See More
yesterday
Jim Gunshinan's blog post was featured
yesterday
Kim Tanner commented on Diane Chojnowski's group Home Energy Pros on Twitter
"Follow The Energy Conservatory on Twitter! We'll follow…"
yesterday

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service