Manny Gonzalez – Pushing Net-Zero Energy From West to East


June 20, 2018

by Manny Gonzalez

The state of California has always been a leader in innovation, especially in construction. In May, the California Energy Commission (CEC) adopted a new statewide mandate requiring solar photovoltaic systems on new homes, including multifamily buildings up to three-stories tall. Exceptions or alternatives will be allowed when homes are shaded by trees or buildings, or when the home’s roofs are too small to accommodate solar panels. No other state in the U.S. mandates solar.

The 2019 Building Energy Efficiency Standards, which take effect on Jan. 1, 2020, focus on four key areas: smart residential photovoltaic systems, updated thermal envelope standards (preventing heat transfer from the interior to exterior and vice versa), residential and nonresidential ventilation requirements, and nonresidential lighting requirements. The ventilation measures improve indoor air quality, protecting homeowners from air pollution originating from outdoor and indoor sources. Furthermore, the new provisions include a push to increase battery storage and increase reliance on electricity over natural gas. Builders installing batteries like the Tesla Powerwall would get “compliance credits,” allowing them to further reduce the size of the solar energy system.

It’s exciting to see how this regulation will alter housing design or pull forward innovation. To get some perspective, I interviewed my colleagues Laurel Gillette, AIA, LEED AP, executive director, architecture; and Bill Ramsey, AIA, principal, KTGY Architecture + Planning, to get their thoughts.

What challenges does this new legislation present? 
Laurel: The mandate raises concerns about escalating home prices and affordability for a state already battling a severe housing shortage and high housing costs. However, the use of solar is expected to save buyers money in the long run, but it will raise their upfront costs at a time when many are already struggling to afford a mortgage. For residential homeowners, based on a 30-year mortgage, the Energy Commission estimates that the standards will add about $40 to an average monthly payment, but save consumers $80 on monthly heating, cooling, and lighting bills.

How will this migrate across the country?
Laurel: This new mandate is not a surprise to many builders who had been pushing to meet the state of California’s New Residential Zero Net Energy Action Plan 2015-2020’s goal launched in June 2015 to have 100% of all new homes meet zero net energy beginning in 2020. There are several national home builders who already have zero net energy homes, most notably Meritage Homes and KB Home. Garbett Homes, headquartered in Salt Lake City, has done the same in Utah with its offering of “Zero-Energy Ready Homes.”

In less than two years, net zero electricity if not net zero energy, will be the new normal here in California, and, historically, what happens in California typically finds its way to other states. Last year, the city of South Miami, Florida, implemented a law that new-home construction must have solar panels. Under the rules, which came into effect on Sept. 18, 2017, new residential construction would require 175 square feet of solar panels to be installed per 1,000 square feet of sunlit roof area, or 2.75 kw per 1,000 square feet of living space, whichever is less. If the house is built under existing trees, the shade may exempt it. We expect that other cities and states outside of California will follow California’s lead.

Bill: In Nevada, there aren’t many financial incentives for builders or buyers to go net zero energy (NZE). They are not being forced by codes or fueled by incentives. In a neighboring state, where there was no NZE code requirement, a forward-thinking builder offered a net zero home option five years ago; however, buyers preferred to upgrade appliances or add a bedroom instead. The challenge has been that buyers want energy efficiency but they don’t want to pay extra for it.

I think that more states will be moving toward net zero energy like California, but it may take a lot longer. Certainly, Nevada builders are mindful of the need for energy efficiency, especially building in a desert climate. The key is a high-performance building envelope using the latest technology and products. For example, the homes at Vu at MacDonald Highlands in Henderson, Nevada, built by Christopher Homes and designed by KTGY, are Energy Star certified. The builder has made a commitment to have all of its new homes Energy Star certified. Each Energy Star certified home reduces greenhouse gases by 3,700 lbs., according to Christopher Homes. KB Home has more than 19,500 homes in Nevada that are 100% Energy Star certified.

The KB Home ProjeKt BUILDER Concept Home will be built in Las Vegas and focus on sustainability in an affordable way. How does that come together in Nevada? 
Bill: As part of Nevada Gov. Brian Sandoval’s effort to promote energy efficiency in the state, the Governor’s Office of Energy (GOE) offered property tax abatements for owners to make their buildings more energy efficient, creating significant energy savings. Through the U.S. Green Building Council (USGBC) or Green Building Initiative (GBI), projects must receive either a Leadership in Energy and Environmental Design (LEED) or Green Globes (GG) certification equivalent to the Silver Level or higher under LEED or Two Globes rating or higher under Green Globes. Depending on the certification level attained and the amount of energy saved annually, the property abatement has ranged from 25% to 35%, with a term from five to 10 years. The GOE is currently undertaking a thorough review of the Green Building Tax Abatement (GBTA) Program.

How will this new legislation impact the KB Home ProjeKt and housing in general? 
Laurel: In the state of California, the series of ABC Green Homes– demonstrations of both good design and cutting-edge technology–are prime examples of how successful the effort to build at zero-net energy can be. As the name describes, they are designed and built to show that “green” buildings can and should be Affordable, Buildable, and Certified, all at a reasonable cost basis to the builder. Partnerships with utility agencies, designers, and product manufacturers allow these homes to show the best of current and forward-thinking technology and materials. Hanley Wood’s previous KB Home ProjeKt’s goal was to be NZE. It wasn’t just the insulation, the housewrap, or the mechanical system, it was how they all work together to create a home that delivers the results that have the least impact on the environment and the pocketbook.

KB Home, headquartered in Los Angeles, is in the final design stages of its ProjeKt demonstration home to be built in Henderson, Nevada, paving the way for other states to move toward zero net energy goals. Notable energy saving features in the KB Home ProjeKt leading to NZE include: 6-inch-deep exterior studs filled with a combination of 3-inch rigid foam insulation and blown-in-batt; ZIP System R-sheathing was selected as the structural wall component providing the exterior water and air barrier and adding R6 to the wall assembly with its built in rigid foam, creating a continuous thermal break between studs and the exterior sheathing; extensive use of indirect daylighting to minimize heat gain; Tesla Powerwall Battery for energy storage from the solar roof; Square D Electrical Load Center with Wiser Energy Hub and Monitoring; Carrier high-efficiency 18 SEER Single Phase VRF Heat Pumps for the home cooling system; high-efficiency appliances from Whirlpool; ZIP System Sheathing and Tape provides an integrated water and air barrier to the structural element of the roof; AdvanTech flooring will be used as the subflooring; and high-efficiency LED lighting from Sea Gull Lighting.

Pacific Gas and Electric (PG&E) is running its Zero Net Energy Production Builder Demonstration Program, which provides energy-related design consultation before, during, and after the home’s construction, providing homeowners with 12 months of monitoring, fully evaluating their home’s energy performance. Recent construction on De Young’s EnVision at Loma Vista community of 36 zero net energy homes teamed with PG&E and found that, at the time of construction, energy upgrades equated to just $8.00 per square foot more than in conventional home construction. This development’s list of energy saving equipment and construction detailing has become standard fare for the NZE community and includes: airtight construction; 2×6 framed walls; dense insulation; dual pane windows with advanced solar control; a high-efficiency air construction system; heat pump water heaters; and smart controls with smartphone capabilities. A study by the builder shows that the homeowner will save more than they will spend with these energy-saving techniques in place.

Bill: As of April 2018, there were 152 buildings in Nevada that are receiving tax abatements from the GOE program. This equates to 175 million square feet of LEED or Green Globes certified space across industries such as office, retail, healthcare, convention, manufacturing, high-rise residential, and hospitality.

These practices are an integral part of how we chose to think about the BUILDER Concept Home, KB Home ProjeKt, putting California’s leadership into action. We collaborated with KB Home and numerous supplier partners to create a design that can be energy efficient and achieve net zero energy.

To learn more about the design and the energy performance of the home, stay tuned to