energy analysis EUIs abnormally high and not changing by much with test "box"

[alex]

I've been trying to learn Revit's energy analysis to get EUIs for single family home projects. I'm a sole prop and looking to figure this out since I use Revit LT for my projects. I've signed on to the 30-day Revit trial (6 days remaining) to get up to speed.

The primary issue is I just don't trust the EUI results. I ran it on more detailed house models and consistently got EUIs that are 3x more than what you'd expect, so I figured I must be setting this stuff up incorrectly. I decided to make a simple test box house.

My Energy Settings are set to the image attached above. Project site is in Atlanta, GA. The Analytical Model looks good. for this "test model." It's basically a box with no windows or doors with two 1000 SF rooms (level 1 and 2). So, I run this thing starting out with a roughly R-20 envelope around the entire box. The EUI comes back as 43.7 kBtu/sf. Compare this to the 2030 Challenge Baseline EUI of 32 (reportedly 2003 CBECS or 2001 Residential Consumption Survey RECS).  Okay. I do a sensitivity analysis boosting the R-value of the envelope to R-40. The EUI comes back essentially the same 41.8. It barely budges. So, I crank up the R-value to a crazy value R-100. Revit spits out an EUI of 41.6.

I remember doing this same box test 2 years ago and basically gave up Revit as an energy analysis tool for single-family houses because of the same issues. I'm wondering if anyone might have ideas what I'm doing wrong. 

Another area of frustration is all the small errors I seem to find that come with Revit. An example is that a few of the Thermal Conductivity data in Revit material thermal properties appears wrong. "Structure, Wood Joist/Rafter Layer, Batt Insulation" is a good example. That's easy to correct but was a pain to troubleshoot.

The larger issue for me is that I can't figure out what I'm doing that gets Revit to spit out these numbers that don't make any sense. EUIs that essentially don't change when the entire envelope R-value is DRAMATICALLY changed.

I've attached the file I created and some images to help. The file is Revit 2025.
https://drive.google.com/file/d/1nvaW70nfgtcbcaW0MUcbfn_PDPBL4VFl/view?usp=sharing

Thanks in advance.
Alex

[barthbradley]

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@alex wrote:

I've been trying to learn Revit's energy analysis to get EUIs for single family home projects. I'm a sole prop and looking to figure this out since I use Revit LT for my projects. I've signed on to the 30-day Revit trial (6 days remaining) to get up to speed.

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You are going to need more than six days.    

[alex]

Here was a similar thread which didn't offer more detailed description of the problem which is why I decided to post this new thread with the actual file. If I'm doing something easy to fix, it should be simple for our more knowledgeable community members to point that out. My interest in resolving this is because I'm considering upgrading from Revit LT to full Revit specifically for the energy modeling. I can't justify that if I can't get answers on why it appears to behave oddly. The additional challenge is that Autodesk doesn't make it easy to get support until AFTER you purchase the software.

Re: EUI values too high - Autodesk Community - Insight