Is Appendix G becoming irrelevant?

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Trying to summarize: 1. We MUST comply with all of the x.4 sections. This covers: * Envelope constructions, min. full & part load SHW, HVAC and "OTHER" efficiencies, voltage drop & receptacle control, lighting controls and exterior lighting power. In addition: 2. the envelope MUST meet 5.5 or what appears to be a very onerous trade-off 5.6 method (Thanks for flagging me; I never saw the alternative method :previously) 3. Lighting power MUST be pretty close to LED levels

That feels like 90+% of the energy use is mandated as minimum requirements. Thus....

... ti seems that creativity is squelched because we're trying to manage only 10% and there is precious little incentive to go through all the effort. Standard 209 is encouraging early design modeling, which I highly favor, but I doubt it will get much traction when the designer can just "plug and play" the mandatory minimums. I'm discouraged.

Jim, I disagree with the use of "MUST" for your #2 above. Maybe in practice, projects typically comply with the envelope in 5.5 in order to achieve the desired savings, but you don't have to if you can achieve the energy savings through a different part of the building. For example, the energy use of large buildings with a relatively small surface area to volume ratio typically isn't affected by the envelope construction since it is internal load dominated. In this case, you don't need to and probably shouldn't comply with 5.5 since money would be better spent on other systems.

...and Joe Deringer, with whom I'm collaborating on a presentation and who teaches the 90.1 course for ASHRAE, agrees with YOU. I think I'm beginning to distinguish now between "prescriptive" and "mandatory". Can't say that the language is very clear in the Standard, but I'm happy to be proven wrong (in this case).

There are two paths for code compliance, following the mandatory and prescriptive requirements of Sections 5-10 (Prescriptive Compliance) or follow Section 11 which requires the design meet Sections 5.4, 6.4, 7.4, 8.4, 9.4, and 10.4 (mandatory requirements only) and can use trade-offs for other items.

App G is an alternative to Section 11 that can be used to quantify performance beyond the 90.1 standard. App G also requires the design to meet the mandatory requirements only and can trade-off other items. Note that exterior lighting power is mandatory in 9.4 but interior isn't (part of 9.5).

ASHRAE 90.1-2016 is a lot more stringent than ASHRAE 90.1-2010. Do you have onsite generation? And are your "50% lighting reductions" versus 90.1-2010 or 90.1-2016?

The building has a 90.1-2010 reduction of 27% (yes, it is not 50%, have 2 projects we're testing and fouled this detail between the two. Other project is still to be compared, but has a 60% reduction. ) Mia culpa on the flub.

Looking at 90.1-2016, this building has a 11% reduction. Verses a 90.1-2016 Appendix G LPD it has a 40% reduction. These are both pretty good reductions while maintaining lighting levels.

No on-site renewable on project. Owner did not want on-site and did not carry any budget. Still achieved a 47% reduction in v4.

As the EUI goes down, plug load becomes a larger percentage of the energy use which is fixed between baseline and proposed. That makes it harder to get a greater % reduction without generating onsite energy. So an 11% reduction seems appropriate.

Also consider that some building codes are moving to net-zero as code in 5-10 years for commercial buildings, and LEED should be leading edge. 11% reduction versus 90.1-2016 isn't really innovative green design anymore, so the 3 LEED energy points seems appropriate. LEED Platinum should be NZE, and LEED Gold should be close to NZE. Get some PV.

May have been a bit unclear - the 11% is only for lighting, it is 11% below 90.1-2016. The building is showing a 5% PCI / PCI_t reduction. For a building that achieves 47% below 90.1-2010 Appendix G that is a huge swing. If this is the intent, then this is more like "LEEDv5". Not some minor incremental update. I'd also be interested to know how/if USGBC did some studies to look at the impact with the percent-to-points table.

The building has an EUI of 42 kBTU/SF; 1/3 of that is plug/misc loads that is held constant. It's realistic for the building use. NZE? No. But good design? Yes.

Also, 'get some PV' is fairly tart & doesn’t match reality on many projects. Project owners will & have balked at this on real projects. Whether its cost, or location (dense urban), or other. I’ve had had that happen, multiple projects. LEEDv4.1 also cut off-site credit significantly.

So, we do load reductions and HVAC studies to inform design. But certification is dismissed. Projects will quit pursing LEED if it does not match the realities of the AEC industry.

Thus, emphasizing Jim’s point of Appendix G may lose its relevancy as a ‘high performance’ standard if not careful.