Page 30 - GB Building Science Ebook 2019

06 SIX CHANGES

THE ZERO NET

ENERGY REVOLUTION

LTHOUGH CURRENTLY SMALL in number, this There’s no doubt construction is changing, and the quality of homes
category of high-performance homes could quickly continues to rise. Faced with the multiple challenges of labor shortages
become the new normal. and material costs, builders can nonetheless build homes tough and
As noted near the beginning of this publication, the tight enough to take advantage of the coming solar renaissance, and
Aage of net zero homes is fast approaching This topic provide a lifetime of pollution-free living for residents. GB
warrants a closer look, as achieving it involves so many other products
and systems. ct best guess there are currently about 5,000 zero net
energy homes in the U.S., mostly in California, along with 7,000 ZNE ZNE CERTIFICATION
multifamily buildings. In 2020 alone, California is expected to add
100,000 new ZNE homes. This sea change is being driven in part by
the mandate requiring solar panels on every new California home SAMPLER
by that date, as noted in the introduction.
But other forces are also in play. According to the Zero Energy Earth Advantage provides Zero Energy and Zero Ready Home
Project, for example, 2019 is a big year for Codes. Three different Certifications.
code types will be updated, creating a triangulation of efficiency
improvement. They include: The Living Building Challenge offers nationwide Net Zero Energy
■ The 2021 International Energy Conservation Code—up for final Building Certification.
■
vote this fall. Passive House Institute offers nationwide Passive House
■ ASHRAE 90.1-2019--Due out this year. Certification.
■
■ Stretch Codes: California, Washington, Vermont and New
■ The Department of Energy has a Zero Energy Ready Certification.
York as well as cities such as Boulder, the District of Columbia, and
Scottsdale—better than IECC or ASHRAE 90.1-2019. The Canadian Home Builders Association launched a Net Zero
One of the immediate challenges to widespread ZNE performance is Energy Home Labeling Program that recognizes homes that reach
finding standards that everyone can agree upon. At present, two of the zero energy ready status, too.
primary players are HERS ratings and Energy Performance Score (EPS). Built Green’s Net Zero Energy Label indicates that a home is
Each has its advocates. HERS measures performance based on plans, modeled to reach zero energy.
relative to a reference home of the same size and shape. Critics say it’s
not accurate enough, because it does not modify results based on overall The Green Home Institute acknowledges homes through the Zero LIST SOURCE: ZEROENERGYPROJECT.ORG
home size, or attempt to measure the building’s actual energy use. Energy Capable Program.
EPS, by contrast, estimates the actual energy use of the specific The U.S. Green Building Council offers LEED Zero to compliment
building, and includes a modification for square footage. their other green building certifications.
Both systems will likely see heavy use as builders rapidly ramp up
to ZNE homes, but it’s a bit of a wild West in terms of certification Code Readiness.
right now. The same might also be said of green building programs, Green Builder’s sister
and in fact there’s plenty of overlap with many of these. They include site, Codewatcher.us,
specific tracks to achieve ZNE performance. monitors thousands of
sources for new rules
LEADING BUILDERS SHOW THE WAY and news on ZNE
mandates, high
Each year, we host an award competition to highlight the nation’s performance homes
most beautiful, efficient homes. Over the past 10 years, we’ve seen and products affected
the number of ZNE homes increase each year, until this year, when by code shifts.
all but one project would have passed that high benchmark.

30 BUILDING SCIENCE SPECIAL REPORT: SIX WAYS CONSTRUCTION IS CHANGING