The lighting power density table and such is completely gone. If I have an interior build-out with more than 100,000 sqft, I'll have to do a full energy modeling for the space for the prerequisite even. Then looking at the percentages for the points, I keep wondering if this won't be a huge disadvantage for older existing building since building envelope will basically be neutral and the existing HVAC system may not be that efficient compared to ASHREA 90.1-2010 or if this is existing to remain too, than what? I have to achieve at least 6% up to 32% energy savings overall with lighting and plug loads?? I have worked on enough LEED projects to know that having envelope and HVAC basically equal will hurt you overall a lot and that's going to discourage our clients from going into an older building or even existing building. I'd like to hear what others think about that.
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Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
962 thumbs up
September 12, 2011 - 5:39 pm
The Energy Model path is just one option. You'll notice that Option 2 - the "Prescriptive Compliance Path" has the lighting power density path you mention. You can get up to 6 points for various lighting strategies via Option 2 in the proposed ID&C rating system.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
September 12, 2011 - 6:17 pm
I think you make a good point Susann. Looks like you are at least partially right - if you have a project over 100k sf and the HVAC doesn't comply with the 90.1 minimum efficiency this leaves the AEDG out and if you don't meet the Core Performance requirements for any system covered you will need to do a model.
Once a space gets this large a model will likely start to make economic sense however. Perhaps we need a major renovation column like BD+C to account for the potential penalty for existing buildings.
Susann Geithner
PrincipalEmerald Built Environments
1297 thumbs up
September 13, 2011 - 10:20 am
I checked again, if I have an office space of more then 100,000 sf than I have only the option to do a model. all other option are restricted to office space less than 100,000 sf.
Marcus, I agree with you I think there should be an option for existing buildings. I also think that a building with more then 100,000sf should still be able to at least meet the prerequisite without modeling. I'm all for raising the bar, but having worked on LEED NC/CS and LEED CI projects I know how much more work and time the modeling adds to the project and for a LEED CI projects it's not really adding value to the project. I will have the same result following the prescriptive requirements for the credits and prerequisites as they are now. Also if I do actually replace parts of the envelope or major pieces of equipment than I may have to certify as LEED NC (major renovation) anyway because of the new MPR guidelines.
I am working on a 260,000 sf office interior at the moment and it's very typical office space for a large cooperation. So the kind of space that makes a difference because of the large scale. This project stretches over 2 years, is done in several phases, and does get changed a lot even during construction, because of developments in the economy, business sectors and such. I have two options than. I do a split review and redo everything for the construction review OR I submit for combined review at the end. The costs and time involved really doesn't leave you an option. We already opt for submitting all those projects for combined review even now under the 2009 version of LEED. Changes and what goes along with it for LEED are made throughout. If we were required to do an energy modeling, I will do it at the end of the project. Otherwise my costs for the LEED documentation are going to prevent my client from doing it at all. Modeling at the end of the project defeats the purpose, I know that. But for me it's going to be, do I do LEED this way or not at all.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
September 13, 2011 - 10:50 am
Also check the EAc1 credit language. You will need to do design phase modeling in order to earn any points. You will not be able to just do a model at the end as this defeats the whole purpose of modeling.
Susann Geithner
PrincipalEmerald Built Environments
1297 thumbs up
September 13, 2011 - 11:48 am
Right. I also notice that EA P2 and EA c1 don't really seem to be aline with each other. If I'm reading it correctly, an office space with more then 100,000 sf will have to use option 1 the modeling for EA P2 to show 6% improvement but could than for EA c1 use option 2 Advanced Energy Design Guide also to gain points?
Also EA c1 option 1 I'm trying to think of 6 measures focused on load reduction other then HVAC. Well the envelope isn't an option unless you consider automatic interior blinds.So lets see what else is possible. Hot water tankless vs tank; lighting controls (occupancy, daylight), plug loads with smart plugs, energy star equipment.
I might be missing something, but I think 6 measures is overkill for LEED CI and also the software and ASHREA let's you use in most cases a percentage discount for occupancy controls. Well what I'm trying to get to is, that the limited options in a LEED CI project a lot of times aren't truly simulated anyway. It's a set discount. That can be done much easier. Time I can actually improving my efficiency. The only reason for doing it would be to see, if a combination of measures would get me to the next point level.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5868 thumbs up
September 13, 2011 - 12:14 pm
Not sure if you would be ale to mix Options. I don't think so but it is a good point for the TAG to consider.
As they say the point is not the points. If this forces projects to re-examine assumed fixed parameters then LEED is doing its job of market transformation. If that means some project don't go through with it then so be it in my opinion.
Also note you have the option of applying previous studies as an option to the specific modeling of an individual project. I agree that we don't have to make this any more complicated than necessary to have the desired effect.