Net-Zero Homebuilder Uses Only Formaldehyde-Free Insulation
Originally published by the following source: Builder Online — November 27, 2017
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In California’s San Joaquin Valley, almost one in six children have asthma, according to the 2015 California Health Interview Survey. For households with affected members, air conditioning is a necessity, not a luxury, especially during the area’s sweltering summers, when temperatures can reach 115 F and air quality becomes unsafe. But energy costs in California are notoriously high and home utility bills can climb into the thousands during the summer. This leaves some residents sacrificing their health and comfort in order to keep costs down.
Fresno-based De Young Properties has long recognized the need for healthy, energy-efficient homes. The company launched its EnergySmart home program in 2008, not long after Brandon De Young, executive vice president and son of founders Jerry and Paula De Young, joined the family business.
“The focus on sustainable home building was going to be important for us, not just for us as a company as it relates to our core beliefs, but also for the home buyers here in our area,” says De Young.
De Young recognized that its buyers would be interested in new homes that would allow them to save on their energy bills and ensure a healthy home environment, especially for families with health issues.
“The air quality in the Central Valley is… some of the worst air quality in the country at times,” De Young says. “And we have some of the highest childhood asthma rates. So that’s a really big deal for our home buyers as well.”
Since the launch of the EnergySmart program, every De Young home has come standard with high-efficiency HVAC filters, low-VOC paints and formaldehyde-free insulation to ensure a healthy home air environment. The program also provides high-efficiency heating and cooling systems, low-Ewindows, extra fiberglass insulation in the walls and roof, and LED lighting, along with optional solar panels. The company has continually expanded and improved its energy-efficiency standards over the years – a process which led it to create its first net zero energy home in 2013.
Now, as the company gears up for California’s 2020 net zero energy goal, it has expanded its existing energy-efficient practices into a community of attainably priced zero-energy homes. The builder partnered with the Electric Power Research Institute (EPRI), Pacific Gas and Electric Company (PG&E), and BIRAenergy to launch the EnVision community, the first grid-connected net zero energy home community to be developed in central California, and the largest in the state. (The next largest, Meritage Homes’ net-zero development Sierra Crest in Fontana, Calif., has 20 homes.)
The 36-unit community is located in Loma Vista, a 3,300-acre master-planned community in Clovis, Calif. The homes are available in one and two-story floor plans, ranging from 1,690 to 3,280 square feet in size with prices starting in the $300,000s. The community opened for pre-sales in September, and sold out 30% of its home sites in the opening weekend. De Young expects to deliver the first homes by the second quarter of 2018.
The individual net zero energy homes De Young built in 2013 and 2017 were the product of a pilot study conducted with Pacific Gas and Energy to determine the cost, design constraints, and challenges of a zero-energy home. The homes served as research and development centers for what would one day become the EnVision community.
“These homes gave us the opportunity to try a lot of new designs and new techniques, and refine and optimize the designs to make them as cost-effective as possible,” De Young says. “It wasn’t until we completed the second zero energy home earlier this year that we finally felt comfortable with all the designs and products that we’ve been trying out over the years.”
While De Young’s standard homes contain 80% LED fixtures, the EnVision homes will have LED lighting throughout, and many of its fixtures and appliances will be Energy Star certified and EPA WaterSense certified. At 16 SEER and 9.5 HSPF, the high-efficiency Lennox HVAC systems used in the EnVision project are a higher grade than those in the EnergySmart home. The houses will also utilize Rheem heat pump water heaters.
The walls use 2x6 wall studs instead of standard 2x4 wall studs, which provides extra space for densely-packed R-21 Owens Corning fiberglass insulation batts. This move required a lot of design work on the part of the structural engineer, as he had to redesign DeYoung’s current floor plans to account for this extra space while still keeping to local building codes.
One of the partnership’s biggest challenges – and accomplishments – was its use of insulation in the attic. In the Central Valley, most attics use loosefill insulation with some vents on the top side of the roof to allow air to circulate. HVAC equipment is usually installed above this thermal boundary, where air temperatures can soar and equipment can overheat. This leads to lower HVAC performance and higher energy bills, DeYoung says. Over four years of research and development, the partnership figured out a way to bring all of the HVAC equipment and ductwork within the thermal envelope by sealing off the attic and insulating under the roof with Owens Corning’s R-38 fiberglass loose-fill insulation, creating a quasi-interior conditioned space.
“We call it our preferred performance-sealed attic,” De Young says.
Historically, one of the biggest obstacles to zero energy at scale has been affordability. De Young Properties and its partners have tackled this issue over almost a decade of testing various products and designs in their prototype Zero Energy homes. “We really spent a lot of time, almost a decade really, of research, developing, and improving to get to this point,” Brandon De Young says. “You could easily get there without doing the R+D, but it would just be really, really costly.”
For example, EnVision’s research and development team decided that the energy benefits of triple-pane glass windows were not worth their high cost. Other component upgrades, including improvements to the thermal envelope and HVAC system, could provide greater energy-efficiency benefits at a lower cost. The community’s solar lease financing structure also saves prospective homeowners from the need to make a massive upfront cash payment for their solar panel systems.
There are also practical challenges to net zero energy communities, such as solar access for homes of varying heights and designs. For instance, a two-story home could block the solar panels of a single-story home next door. To prevent this, DeYoung is only offering certain plans in certain areas of the community in order to optimize the community’s exposure to sunlight.
As a side benefit, while some of the building methods and products used in EnVision may not be common in the Fresno area, De Young predicts that they will become more accessible over time as they become more commonly used.
“The heat pump [water heater] is not common around here, so manufacturers and plumbers have to special order these advanced products. However, the more that this type of home design is built, the more that that product becomes commonplace. And therefore the manufacturers are able to bring their pricing down because of scale.”
Over the next several years, De Young intends to improve on its initial community model with more grid-friendly strategies and improvements in new home designs. While there are no official plans for another De Young net zero community, he has no doubt that EnVision’s model is reproducible on a wide scale, and that other builders will follow in the community’s footsteps – especially as California’s building codes creep closer to requiring net zero energy--at every price point.