See all forum discussions about SD Leaders

Subscribe to new posts about SD Leaders Post a new question aboutSD Leaders

Forum discussion

AIA 2030 - Zero tool vs CBECS baseline

Emily Purcell

Sustainable Design Lead

CannonDesign

LEEDuser Expert

379 thumbs up

March 30, 2022

hi all! I'm almost at the finish line with this year's 2030 reporting...whew. I'm running into an issue that I wanted to throw out to this group, regarding the zero tool and national average baselines. Hoping some of y'all who manage your firm's 2030 data, or are just more familiar with CBECS and related data, have some insight / experience to share.

These baseline numbers have been very different for us since the launch of the new DDX and the move from national average to Zero Tool in setting baselines. For example, I reported two high-rise multifamily buildings in Chicago. One was reported in 2017 and one in 2021, both complied with the Chicago energy code via the performance path (2015 / 2018 IECC respectively), both using the Residential - MidRise / High Rise use type.

The 2017 project was assigned the national average baseline of 79 kbtu/sf/yr. The pEUI was 51 for a savings of 35% - consistent with AIA's estimated savings for projects using the 2015 IECC.

The 2021 project was assigned the Zero Tool baseline of 50 kbtu/sf/yr. The pEUI is 53 for a savings of -8%.

So...this makes it difficult to accurately look at our year over year progress - right now my line graph shows our AIA 2030 % savings falling, but our energy intensity on modeled projects is also falling. Not to mention, when I report energy model results like the above examples, my % savings is much worse than when I report that a project hasn't been modeled yet or is following prescriptive code.

Whatever happens within the DDX, I'd like to standardize our internal records. But we're kind of drawing a blank on how to choose! The national average EUI isn't climate-specific and I'm not sure how old it is. But the Zero Tool seems, across the board, low for the project type / climate. It's consistently lower than the code baselines our energy modelers are generating, and code baseline should in theory be better than typical existing.

Has anyone else seen their AIA 2030 performance fall dramatically for this reason? How are you addressing the change? Thanks for any insight!

Post a reply

Mike Manzi

Bora Architects

LEEDuser Basic Member

0 thumbs up

Wed, 03/30/2022 - 22:09

I just submitted ours. Whew is right! I've noticed changes, too, but some of our baselines have actually gone up. I used to use 120 for higher ed work and the numbers I'm getting now are ~130. Similarly though, some project types look much better for the ones that are not modeled using code values (Oregon is now aligned with ASHRAE 90.1-2019) than the modeled ones, especially for us in affordable housing. I think there are limitations to how 2030 data can be used to track an individual firm's progress consistently, though we haven't established an alternative yet.

Katie Ackerly

Associate / Sustainability Lead

David Baker Architects

LEEDuser Basic Member

0 thumbs up

Wed, 03/30/2022 - 23:29

yes this has been a particularly difficult moving target for multifamily buildings. 78.8 as the national median baseline for multifamily was around for a while and i thought was clearly not correct or helpful (except to feel successful at meeting 2030!) - i think it's some CBECS catch-all because it's listed for mixed-use and other types (someone correct me if they know where this number originally comes from). Portfolio Manager has since replaced it with 59.6 based on Fannie Mae database which feels more realistic. Zero Tool was migrated from Target Finder which gave you a baseline that was weather-normalized and normalized for various building parameters like height and unit count, like zero tool, but based on my understanding was still supposed to still be a national median (ie not *climate *normalized) - when i first noticed that the zero tool baselines were significantly lower across the board i assumed maybe they did do some regionalization since the number seems to change with location and we work in a mild climate...at some point i stopped trying to figure it out :) ANYWAY... I basically address this by not caring too much about our percent reduction. This can be annoying, though, for awards that are based on 2030 performance. Why can't we just have a target site EUI (gross and w/ PV) by building type, again? the percent reduction introduces all this complication to something that could really be so much more to the point. I have set a target EUI of 20 for our buildings not counting PV based on NREL's most recent detailed benchmark modeling for multifamily combined with my own experience (i'm very happy if we get under 25, especially if *actual *use gets under 25) - we have plenty of work to do to make this a reality across our portfolio, with buildings predicted to be 21 EUI by an imperfect modeling method often using double that. So I have been really trying to focus on this with our staff. katie

Emily Purcell

Sustainable Design Lead

CannonDesign

LEEDuser Expert

379 thumbs up

Thu, 03/31/2022 - 13:21

Thanks Mike & Katie! Good to know this is a common struggle at least? Agreed that the real challenge here is figuring out what I actually want the data for. It's great to have the snapshot of year-over-year progress (but not enough progress...) and a comparison of our overall performance versus where codes are at and the industry average that AIA reports out - we share that at new staff orientation and it's the simple chart the executives want to see. (We're hoping to share it again this year in time for Earth Day, and that probably means just reverting to the 78.8 EUI for the sake of getting that done in time and not dragging the execs into the data weeds with us.) I like that year-over-year to identify things we're consistently doing well and not so well. I also like having the 2030 numbers as a hook for engaging staff on what an EUI is and what a "good" EUI is. But of course I know it's not a perfect benchmark and I guess this baseline shift is forcing the issue instead of letting me ignore it :)

Kyleen Rockwell

Senior Sustainable Design Engineer

LEEDuser Basic Member

0 thumbs up

Thu, 03/31/2022 - 13:48

The DDx Baseline struggle is real. What we do for our projects with an energy model of the code baseline is take the code baseline pEUI and adjust the DDx Baseline to match the approximate code equivalent savings https://transform.aia.org/confluence/display/DDXWIK/Add+Design+Energy+Code that way at least our proposed pEUI makes sense and we can put more reliability in our percent savings of our portfolio. For example, an ASHRAE 90.1-2010 baseline pEUI of 80 would make the DDx Baseline 138 (calculated so that there is the code equivalent 42% savings between DDx and 90.1-2010 baselines) and our proposed pEUI we leave at what was modeled. The ultimate goal is carbon neutral so the baseline dance really shouldn't be necessary since at the end of the day we want 100% savings. But we find the baseline adjustment method keeps our dataset more realistic, if our energy models show 10% better than code they should not be worse than the DDx baseline. Of course the code equivalent savings are not a perfect reflection for unique use types but it's the best we have so that we don't have project teams discouraged by low % savings.

Emily Purcell

Sustainable Design Lead

CannonDesign

LEEDuser Expert

379 thumbs up

Thu, 03/31/2022 - 17:08

That makes sense - might be a good way to normalize the data quickly until we can think through a more long term change. Thanks!

Katie Ackerly

Associate / Sustainability Lead

David Baker Architects

LEEDuser Basic Member

0 thumbs up

Fri, 04/01/2022 - 04:48

That's an interesting approach, Kyleen. So you're essentially claiming the percent reduction below what you think your baseline model is already achieving from a 2030 baseline...we actually did something similar in the very early days before we had any site use at all - we only had CA T24 TDV and percent code improvement from some of our consultants. Do the numbers make sense? in other words, is 138 something close to what you'd expect for the building type in question? I agree Emily, the most useful thing is to do whatever you're doing consistently year over year so you can communicate progress!

Emily Purcell

Sustainable Design Lead

CannonDesign

LEEDuser Expert

379 thumbs up

Fri, 04/01/2022 - 13:36

I used Kyleen's suggestion for the 5 projects that were showing negative savings. It did bring them in line with the savings of comparable projects from past years. Our overall portfolio is still showing moderately worse performance compared to previous years, which isn't great as I know our EUIs got a little lower across the board, but it's a start! The affected projects were all large high-rise multifamily in cold and hot climates (Hawaii, Virginia, Ohio, Illinois) so that tells me the Zero Tool baseline isn't capturing something about heating/cooling at that scale accurately...