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: 240

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

Discussion Forum

Basic Heat loss information

Started by Luis Hernandez. Last reply by tedkidd Oct 30, 2014. 1 Reply

How to model a skylight

Started by Luis Hernandez. Last reply by Luis Hernandez Oct 16, 2014. 2 Replies

Modeling the apartment upstairs

Started by Luis Hernandez. Last reply by Ethan MacCormick Sep 26, 2014. 2 Replies

Modeling a Townhouse

Started by Luis Hernandez. Last reply by Luis Hernandez Jul 7, 2013. 4 Replies

Latest Activity

Profile IconM Johnson and Jerry Phillips joined Home Energy Pros Forum
5 hours ago
Sara Watson posted a blog post

6 Tips to Pick Out The Best Solar Outdoor Lights

You have a beautiful home in Florida and plan to add a little sparkle to your front garden, patio,…See More
22 hours ago
DesignTech liked DesignTech's photo
yesterday
Anthony Roy is now a member of Home Energy Pros Forum
yesterday
Barbara Smith commented on Barbara Smith's video
yesterday
Barbara Smith replied to Jignesh's discussion Efficiency of furnace
"Installation and proper sizing is important to getting the best performance out of your furnace.…"
yesterday
Barbara Smith replied to Jignesh's discussion Best brands for furnace
"Check ENERGY STAR and Consumer Reports.…"
yesterday
Barbara Smith replied to Diane Chojnowski's discussion Support Mike Rogers, a long-time home performance hero, as he battles sinus cancer. in the group News & Announcements
yesterday
Barbara Smith joined Diane Chojnowski's group
Thumbnail

News & Announcements

Share your news and announcements with the community in this group.To post news or an announcement,…See More
yesterday
Diane Chojnowski added a discussion to the group News & Announcements
Thumbnail

Support Mike Rogers, a long-time home performance hero, as he battles sinus cancer.

Support Mike Rogers, a long-time home performance hero, as he battles sinus cancer. Write a note, a…See More
yesterday
Eric Kjelshus replied to Jignesh's discussion Efficiency of furnace
"I like looking at system efficiency - Lets say the you have a 95% gas using furnace 100,000…"
Monday
Cameron Home Insulation replied to Jim Conlon's discussion Insulation Blower Recommendations?
"Hi, Rent a Cellulose Insulation Blower from your local Home Depot. Get more information about…"
Monday
Todd Abercrombie liked Barbara Smith's video
Saturday
Jim Hensen replied to Jignesh's discussion Efficiency of furnace
"Great question - what the efficiency rating means is one of the most common questions we we asked.…"
Saturday
Michael Schettine's blog post was featured

Framing production combined with air sealing

Building Tighter Homes with Gasketed FramingIf you follow our blog, you know that we talk quite a…See More
Friday
Profile IconMichael E and Jason Dion joined Home Energy Pros Forum
Friday
Jason Dion joined Sean Lintow Sr's group
Thumbnail

Best Practices (Residential)

Best Building, Retrofitting, or even Auditing Practices - what are they, what should change, what…See More
Friday
Jason Dion joined Michael Stuart's group
Thumbnail

INFRARED THERMOGRAPHY USERS

This group is dedicated to knowledge sharing and discussion of infrared thermography for building…See More
Friday
Jason Dion joined allen p tanner's group
Thumbnail

Energy Auditing Equipment for Sale, Trade or to Purchase

Discuss the pros and cons of the equipment you are interested in prior to purchase. Post equipment…See More
Friday
Jason Dion joined Allison A. Bailes III's group
Thumbnail

HVAC

HVAC design, Manuals J, S, T, & D, Duct leakage, Air flow, ENERGY STAR new home requirements,…See More
Friday

Photos

  • Add Photos
  • View All

© 2018   Created by Home Performance Coalition (HPC)   Powered by

Badges  |  Report an Issue  |  Terms of Service