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: 280

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

Jim Gunshinan's blog post was featured

Zero-Energy Homes Are Ready for Mainstream Markets

By Alisa Petersen and Michael GartmanZero-energy (ZE) homes—efficient homes that produce or procure…See More
14 hours ago
Jim Gunshinan posted a blog post

Zero-Energy Homes Are Ready for Mainstream Markets

By Alisa Petersen and Michael GartmanZero-energy (ZE) homes—efficient homes that produce or procure…See More
16 hours ago
Chris Davis's event was featured
Thumbnail

Webinar: The Latest Facebook + Google Changes and How They AFFECT You! at https://www.crowdcast.io/e/the-latest-facebook-

October 24, 2018 from 5pm to 6pm
As the BIG names in online experience - Facebook + Google - continually make headlines on how they…See More
20 hours ago
David Byrnes's video was featured

Static pressure measurement on a package heat pump

Measuring static pressure on a package unit
20 hours ago
Chris Davis posted an event
Thumbnail

Webinar: The Latest Facebook + Google Changes and How They AFFECT You! at https://www.crowdcast.io/e/the-latest-facebook-

October 24, 2018 from 5pm to 6pm
As the BIG names in online experience - Facebook + Google - continually make headlines on how they…See More
21 hours ago
Profile IconChris Davis, Pamela Denlinger, Vincent Amoroso and 1 more joined Home Energy Pros Forum
21 hours ago
Brett Little posted an event
Thumbnail

The Economics of Zero Energy Homes: Single Family Insights - Free CE Webinar at Webinar Online

October 24, 2018 from 12pm to 1:15pm
Zero-energy (ZE) and zero-energy ready (ZER) homes currently comprise less than 2% of single family…See More
yesterday
Mandy Leazenby replied to Allison A. Bailes III's discussion ENERGY STAR Version 3
"I've only ever worked on Energy Star with Habitat for Humanity.  But we have very few…"
yesterday
Colin Genge is now a member of Home Energy Pros Forum
yesterday
Brett Little posted a discussion

How to become a Certified GreenHome Professional - Free Webinar!

The Certified GreenHome Professional (CGHP) training is a way to learn about the basics of…See More
Sunday
Corbett Lunsford's video was featured

Testing Air Quality with Your Nose: Control Your HOMEChem

Charlie Weschler sits down with Grace and Corbett and gives fascinating examples of the complexity of indoor air chemistry. He is an air quality legend, a professor on three continents, and a super nice guy.
Friday
Profile Iconwallace van, Tony kroos and Sunmar Construction, Inc joined Home Energy Pros Forum
Friday

Photos

  • Add Photos
  • View All

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

Badges  |  Report an Issue  |  Terms of Service