Inside LEED v4: The view from the MEP engineering seats

The 44,640-sf Iowa Utilities Board/Office of the Consumer Advocate Building in Des Moines, completed in 2011, was built at a cost of $227/sf and earned Platinum certification under LEED 2.2. Scott Bowman, PE, who worked on the building while at KJWW Engineering Consultants, said previous-generation Platinum buildings like this one could have trouble reaching Gold or even Silver under LEED v4. PHOTO: COURTESY KJWW ENGINEERING CONSULTANTS

Much of the spirited discussion around LEED v4 has been centered on the Materials & Resources Credit. At least one voice in the wilderness is shouting for greater attention to another huge change in LEED

Much of the spirited discussion around LEED v4 has been centered on the Materials & Resources Credit, Building Products Disclosure and Optimization – Material Ingredients—especially with regard to building products containing substances that could be toxic to humans or the environment.

At least one voice in the wilderness is shouting for greater attention to another huge change in LEED: the shift to ASHRAE 90.1-2010 as the new reference standard for Energy & Atmosphere prerequisites and credits. “That’s the real story in LEED v4, from an MEP point of view,” says Scott Bowman, PE, LEED Fellow. “The change to 90.1-2010 makes v4 much more rigorous.”

Bowman, who recently retired as Corporate Sustainability Leader at KJWW Engineering Consultants (where he was involved in 119 LEED-certified projects), says Building Teams need to start warning their clients that it’s going to be a lot tougher to reach LEED Gold or Platinum under v4. He says that some of the 14 LEED Platinum projects that he worked on at KJWW might barely squeak by with a Silver or Gold rating under v4.  Projects that were Silver or Gold might not even reach certified.

“We need to be working on our clients’ expectations now, because the changes that are coming are going to be significant,” says Bowman, who recently established his own consultancy, Integrated Design + Energy Advisors, known as IDEA. “Our clients should know that we may have to do a couple more runs on the energy modeling for the design”—and that could mean additional fees.

“We had a major jump from 90.1-2004 to 90.1-2010,” says Bowman, a second-generation engineer. He points to data from the Energy Department’s Pacific Northwest National Lab: energy use intensity (EUI) was reduced 4.5% moving from ASHRAE 90.1-2004 to 90.1-2007, but 90.1-2010 brings it down a much more demanding 18.5%.

LEED v4 buildings will have to be 30% better on EUI improvement just to meet the prerequisite, he says, “and they have to go even higher to get EA points.”

Key technical improvements in v4 EA credits, according to Bowman:

•  Minimum energy performance has to be 5% above ASHRAE 90.1-2010, 3% for renovation projects; minimum Energy Star rating must be 75 or better.

• Building-level energy metering is now required for all buildings.

• Demand response is now a credit. Projects can earn up to two points for installing systems necessary to participate in a demand response program. Projects located in areas with no demand response program can earn a point by making the building ready to engage in such a program. “The idea of preparing buildings for demand response is a good one,” says Bowman.

Strategies that once were nice-to-haves are now required. “If you have clerestories and skylights, you have to have daylighting controls,” says Bowman. “Before v4, it was a strategy, now it’s a requisite.” Lighting power density is also much more stringent, he says.

Building Teams are going to have to reach higher in their building envelope designs, says Bowman. “You can’t rely on the mechanical/electrical system alone to help you comply with v4,” he warns. “You only get one chance with the envelope. Some of our 100-year-old buildings still have single-pane glass! We need to encourage clients to invest more in good windows, walls, and roofs.”

A similar philosophy guides the use of renewables in LEED v4: the project must meet the requisite energy performance levels before renewables can be applied. “The idea in high performance is: first, use less energy; then, use it efficiently; and then, and only then, make it on site, via renewables,” says Bowman. “You can’t use PVs to make up for a bad building.”

Measurement and verification credits have been heavily modified under v4, in Bowman’s view. “Under LEED 2009, M&V attempted to guide projects to measure energy use on a much more granular basis than before, but it was not implemented very much, and it really was more of an operational credit,” something that should be in LEED EBOM, he says. LEED v4 sets a prerequisite for building-level energy metering. “That’s not going to be a problem for 99% of LEED v4 projects,” says Bowman. The only possible exception: campus projects.

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