Hi all,
We’re working on an EBOM Project in Finland (Educational Building) and are about to fill in the Case 2 Calculator for EAp1 (Option1 Tab). We are now wondering what the difference is between the Annual Weather Normalized Source Energy Intensity and the Current Weather Normalized Source Energy Intensity to be found from EPA’s Portfolio Manager. Can we divide the Current Weather Normalized one by 12?
Can anyone help?
You rely on LEEDuser. Can we rely on you?
LEEDuser is supported by our premium members, not by advertisers.
Go premium for
Ravi Bajaj
Education ManagerSan Diego Green Building Council
9 thumbs up
January 24, 2013 - 6:32 pm
Stefanie,
It seems that EnergyStar has changed some of their nomenclature recently, and that may be the source of confusion. Looks like the "Current Weather-Normalized Source Energy Intensity" actually represents your "Annual Weather-Normalized Source EUI"
See definition from EnergyStar website for "Current Weather-Normalized Source EUI":
"the weather-normalized source energy intensity (kBtu/Sq. Ft.) for the current 12-month period"
Stefanie Hoffmann
HAAGA HELIA OY Ab6 thumbs up
January 25, 2013 - 3:47 am
Thank you a lot for your quick reply, Ravi.
It seems that now we won't even fullfill the prerequisite. With such a high Weather Normalized Source Energy Intensity (475.6) we are far, far away from complying with the prerequisite. I don't even understand how this is possible with such a new building and 44% share of renewable energies.
David Eldridge
Energy Efficiency NinjaGrumman/Butkus Associates
67 thumbs up
February 14, 2013 - 3:07 pm
Have you looked at any of the energy audit or commissioning credits yet?
There might be some use of your building out of the normal for "educational" type buildings -- perhaps a lot of computing energy, or educational laboratory spaces?
Stefanie Hoffmann
HAAGA HELIA OY Ab6 thumbs up
February 19, 2013 - 7:11 am
Thank you for your reply, David.
We havn’t looked into energy audit credits yet but what I can tell already is that our University building doesn’t include any special, energy-intensive spaces; mostly classrooms, offices and a cafeteria. Plus, all computers are energy-star labeled.
What we did figure out though is that the high Current Weather Normalized Energy Source Intensity occurred due to a conversion mistake. Nonetheless it is now, with a value of 145.0, still too high to meet EAp2.
Does anyone have experience in using a local benchmark for projects outside the U.S.? And by comparing the “normal” Reference Guide with the one including the Global Alternative Compliance Paths it’s not clear to me whether or not we have to use the Case 2 Calculator. Any hints?
I really appreciate your help!
Ravi Bajaj
Education ManagerSan Diego Green Building Council
9 thumbs up
February 19, 2013 - 2:36 pm
I am not sure about international projects with regard to the EAp2 Case 2 calculator unfortunately.
Two things I would suggest looking into however:
- What is the baseline or median EUI against which you are comparing. In many cases, when you put "Other" space-type into Portfolio Manager, you are given a baseline or median EUI around 94.0, whereas the off-line LEED calculator will generate a reference EUI based on the square footage of each space you have: classroom, office, etc.
- If you are trying to "self-normalize" your EUI based on occupancy or other weather data you have, there is an EPA document entitled "Guidance for Normalizing Environmental Performance Results" from 2004 that outlines options for normalizing other operating characteristics.
Hope this helps, I apologize for not having more information regarding international projects.
Stefanie Hoffmann
HAAGA HELIA OY Ab6 thumbs up
February 27, 2013 - 4:08 am
Thank you for your help, Ravi!
Well, Portfolio Manager uses 144.0 as National Median Source EUI for the Space “Other-Education”. The offline LEED calculator uses for the same space type a value of 115. With our Current Source EUI of 145.0 and with 70% educational space out of the total area; we won’t meet the prerequisite.
What I’m still wondering about is this “National Median Source EUI” Portfolio Manager as well as the Offline Calculator is comparing to. “National” refers to the U.S.; so it’s comparing the energy performance of our project building towards U.S. buildings. And I don’t really see how that makes sense since it is freezing cold in Finland most of the year, so heat consumption is huge. And it’s also very dark the whole winter, so I assume we use more electricity for lighting etc.
Phew; this all seems so complicated to me.
Eric Johnson
271 thumbs up
February 27, 2013 - 8:05 am
Stefanie,
I suggest reading the following to better understand the energy benchmarking methodology of Energy Star - Portfolio Manager Overview- Technical Descriptions for Models Used in the Rating System This document provides detailed information on the methodologies used to create the energy performance ratings including details on rating objectives, regression techniques, and the steps applied to compute a rating.
http://www.energystar.gov/ia/business/evaluate_performance/General_Overv...
http://www.energystar.gov/ia/business/evaluate_performance/k12school_tec...
You could try getting in touch with the people who worked on the Intelligent Energy Europe project Energy Performance Assessment of Existing Non-Residential Buildings for a benchmark building http://www.epa-nr.org/22.html the report on Finland can be found at the link provided.
Stefanie Hoffmann
HAAGA HELIA OY Ab6 thumbs up
March 12, 2013 - 10:32 am
Hi Eric,
thanks for the additional information. I read through the different documents and it confirmed what I knew from an Energy Star support employee already; the 2003 CBECS (on which most ratings are based) didn't include any international facilities. So the benchmark of our project building is relalised towards buildings of that type in the U.S.. Or as the staff member of Energy Star explained, the benchmark shows how a Finnish building would operate in the U.S. under Finnish weather conditions.
In my eyes this still doesn't make sense when the requirements of EAp2 are to compare the project building's energy performance to the NATIONAL average.
Thanks also for the last link; I will try to get in touch with someone who worked on the Intelligent Energy Europe Project.
Eric Johnson
271 thumbs up
March 12, 2013 - 11:10 am
Stefanie,
Energy Star accounts for differences in weather via HDD and CDD.
"HDD and CDD are common measures that reflect the heating and cooling requirement of a building, relative to the average temperature. These variables are included in the EPA regression analysis. By including these variables in the regression analysis, EPA can estimate adjustments to reflect the typical relationship between HDD and energy intensity and between CDD and energy intensity. In most rating models, HDD and CDD are determined to have statistically significant impacts on energy use. Therefore, they are included and adjusted for in EPA ratings."
While using Energy Star to benchmark the energy performance of buildings isn't perfect; it is currently the most robust and statistically valid method I've seen. If you look through the data at the link I sent and compare it to CBECS you'll understand.
Eric Johnson
271 thumbs up
March 12, 2013 - 11:36 am
Stefanie,
If you want to compare your building to the education buildings listed in EPA-NR Survey: National context and need for instruments May 2005 (I'm not sure how or what this number includes; see page 3) the average Finnish education building uses 229 kWhm2.
Stefanie Hoffmann
HAAGA HELIA OY Ab6 thumbs up
March 13, 2013 - 6:55 am
Thank you for your quick reply, Eric!
the regression analysis itself makes sense to me. Just the fact that Portfolio Manager then uses the results to compare it to U.S. buildings is confusing in my eyes since EAp2 requires the comparison to the NATIONAL average.
Anyways, I'll try to figure out a way to use a local benchmark.
Eric Johnson
271 thumbs up
March 13, 2013 - 7:04 am
Stefanie,
You might try Timo Rintala at the Finland GBC who is a member of the LEED International Roundtable and is trying to solve these sorts of issues.
If you manage to find a good source of EU wide building energy usage information please post a link to it.
Stefanie Hoffmann
HAAGA HELIA OY Ab6 thumbs up
March 13, 2013 - 7:25 am
I contacted someone from FIGBC a couple of weeks ago but he couldn't help. But thank you for the hint. I'll get in touch with Timo.
And sure, as soon as I find useful information, I'll post it here!
Ravi Bajaj
Education ManagerSan Diego Green Building Council
9 thumbs up
April 2, 2013 - 6:58 pm
Stefanie, Eric,
This is always such a complex aspect for LEED for Existing Buildings projects not eligible for the conventional Energy Star score (or National Energy Performance Rating). Fortunately, it is to a project's own benefit to understand the best possible benchmark with which to compare your building. In my minimal international project experience, I can offer the two notes below:
- Regarding the space type you have: if 70% of your space type is "Education", you should also include the gross square footage for any "ancillary support areas" (storage, admin, lobby, office, etc) under the "Education" space type. You should split other space types out only if they do not directly support the Education function, or if there is at least a 10% difference in operating hours in any enclosed spaces.
- For international projects, the two compliance paths for this prerequisite are listed in the LEED ACP (or Alternative Compliance Paths for Projects Outside the US):
1 - Benchmark against any national energy data (if available)
2 - Compile source energy data for at least three comparable buildings, and demonstrate energy efficiency at least 19% better than this baseline
3 - there exists a pilot credit called "Energy Jumpstart" that allows you to create an energy baseline using 5 years historical data, against which you must demonstrate energy efficiency improvements.
Hope this helps, and please feel free to email me (ravi@usgbc-sd.org) for any clarifications or anything. Seems like Eric is also a great resource for international work as well.