As California moves toward its 2020 mandate requiring all new homes to produce as much energy as they consume annually, builders across the country are paying close attention to pioneering projects that prove the concept is viable today. The Sierra Crest development in Fontana, California, stands as one of the first net-zero energy communities in the state, offering valuable lessons in residential construction that balances energy performance with affordability. This project, led by the Electric Power Research Institute (EPRI) in partnership with Meritage Homes, demonstrates that affordable net-zero energy homes are achievable with current technology when builders commit to integrated design and construction strategies.
The Sierra Crest Net-Zero Community: A Blueprint for Residential Energy Performance
Situated 50 miles east of Los Angeles in Fontana, California, the Sierra Crest development comprises 187 lots divided into three distinct communities. Within this larger subdivision, 20 homes are designated as net-zero energy houses split between two neighborhoods. The Grand Canyon neighborhood contains 9 net-zero homes, while the Yosemite neighborhood hosts 11 clustered together. This dual-cluster design allows researchers to study how different configurations of solar and battery storage affect grid integration at the community level.
Project Participants and Research Objectives
The Electric Power Research Institute leads the research effort with support from key industry partners including BIRAenergy, Itron, and Southern California Edison. The California Public Utilities Commission will use data from this project to inform policy decisions as the state prepares for its 2020 net-zero mandate. Over several years, researchers will study how these houses and their advanced technologies integrate into the utility grid, while simultaneously exploring ways to improve scalability and economic feasibility across the state.
Home Sizes and Pricing
The net-zero energy homes at Sierra Crest range in size from approximately 1,900 to 2,900 square feet, with prices ranging from about $379,000 to $432,000. The HERS (Home Energy Rating System) scores on these houses average negative 3, meaning they produce more energy than they consume. This is a remarkable achievement considering California’s already stringent Title 24 energy code requirements.
Building Envelope and Framing Strategies for Net-Zero Performance
The construction methods used at Sierra Crest offer practical insight for builders looking to achieve high-performance residential construction. Meritage Homes, the eighth largest homebuilder in the United States, has focused on energy-efficient construction for over six years and now offers solar and net-zero performance options on every home it builds nationwide.
Wall Assembly and Insulation
The wall assembly at Sierra Crest uses advanced framing techniques with 2×4 stud walls. The thermal envelope includes:
- Continuous layer of R-5 polystyrene insulation on the exterior of walls
- Open-cell polyurethane foam insulation in stud cavities
- Total assembly R-value of approximately 19
- Conditioned attics insulated with 6 inches of open-cell foam (roughly R-24)
Meritage follows a performance-based compliance path under California’s Title 24, which allows builders to demonstrate overall energy performance rather than meeting every prescriptive requirement individually. This approach provides flexibility in material selection while maintaining high efficiency standards.
Air Sealing and Fenestration
Airtight construction is critical to net-zero performance. The Sierra Crest homes achieve air leakage rates between 1.0 and 1.2 air changes per hour at a pressure difference of 50 pascals (ACH50). This level of airtightness requires careful detailing of the air barrier system and rigorous quality control during construction. The windows specified for these homes feature:
- Low-emissivity (low-e) coatings
- Double-glazed assemblies
- Solar heat gain coefficient of 0.22
- Whole-window U-value of 0.34
These window specifications minimize heat gain during California’s hot summers while allowing beneficial daylight, reducing both cooling loads and lighting energy requirements.
Slab and Foundation Details
The foundations at Sierra Crest use uninsulated, post-tensioned concrete slabs. While insulation below the slab could improve thermal performance marginally, the mild climate of Climate Zone 3 (Fontana’s classification) makes this a cost-effective trade-off. Builders in colder climates would need to add slab edge and under-slab insulation to achieve similar performance levels.
Mechanical Systems and Renewable Energy Integration
The mechanical systems chosen for the Sierra Crest homes reflect a holistic approach to energy efficiency where every component contributes to the net-zero equation.
Heating, Cooling, and Water Heating
All homes are equipped with heat pump technology for both space conditioning and water heating. The key systems include:
| System Component | Type | Energy Efficiency Benefit |
|---|---|---|
| Space heating and cooling | Variable speed air-source heat pump | Matches output to demand, reduces cycling losses |
| Domestic hot water | Heat pump water heater | 2-3x more efficient than electric resistance |
| Lighting | LED throughout | 80% less energy than incandescent |
| Photovoltaic system | Grid-tied PV, 4 kW average capacity | Offsets annual energy consumption |
| Battery storage | Lithium-ion, 3 kWh per home or community-scale | Shifts solar production to evening peak |
Variable speed heat pumps are particularly effective in net-zero homes because they modulate their output to match the heating or cooling load precisely, avoiding the efficiency penalties associated with cycling on and off. This technology pairs well with tight building envelopes and high-performance windows to maintain comfort with minimal energy input.
Solar PV and Battery Configuration
The photovoltaic systems at Sierra Crest average 4 kW of capacity and are grid-tied. The research design compares two battery storage configurations that will help utilities understand the best approach to clean energy solutions for home builders:
- Individual batteries: In the Grand Canyon cluster, each home has its own 3 kWh lithium-ion battery provided by SunPower. This configuration allows homeowners to store their own solar production for evening use.
- Community battery: In the Yosemite neighborhood, all 11 net-zero homes connect to a single, larger battery. This shared approach may offer cost savings and more efficient load balancing across multiple homes.
In both configurations, batteries serve to flatten the load on the grid throughout the day rather than providing long-term backup power. The goal is to address what the utility industry calls the duck curve the phenomenon where solar production peaks in midday while demand spikes in the evening as the sun sets and PV production drops.
Smart Controls and Thermal Mass
CR Herro, vice president for environmental affairs at Meritage, emphasizes that optimizing net-zero performance requires rethinking traditional design assumptions. He advocates for orienting solar panels toward western exposure rather than southern exposure to better match afternoon demand peaks. Smart ventilation practices, intelligent HVAC controls, and the reintroduction of thermal mass into building design all play important roles in leveling the energy load profile of highly efficient homes.
Market Adoption and Cost Considerations for Builders
Despite the proven technology and relatively modest additional costs, market adoption of net-zero homes remains surprisingly low. Meritage can offer a net-zero option to any homebuyer nationwide for a modest price premium, yet only about 1 percent of buyers choose it.
The Cost Equation
For a typical 2,800-square-foot Meritage home, adding enough solar panels to achieve net-zero performance costs approximately $12,000. When this cost is rolled into a 30-year mortgage, the monthly payment increase is more than offset by the reduction in energy bills. This means homeowners see positive cash flow from day one.
Consumer Awareness Barriers
The primary barrier to widespread adoption is not cost but awareness. As Herro explains, homebuyers are often overwhelmed by location, design, and price considerations and do not realize they can demand high-performance features from their builder. As buyer sophistication grows and consumers begin expecting more from new homes, the market will shift. Builders who position themselves now to deliver net-zero performance will have a competitive advantage when demand inevitably increases.
Key Takeaways for Builders
For builders considering net-zero construction, the Sierra Crest project offers several actionable lessons:
- Integrate energy modeling early in the design process to optimize the building envelope before specifying mechanical systems
- Use advanced framing and continuous insulation to achieve a tight, well-insulated enclosure without excessive cost
- Specify heat pumps for both HVAC and water heating to maximize efficiency with a single technology platform
- Design for solar readiness even if PV is not installed immediately including conduit runs and roof layout that accommodate future panels
- Consider battery storage configurations that align with local utility requirements and grid interconnection policies
- Educate homebuyers about the long-term financial benefits of net-zero performance to increase adoption rates
Builders who master these strategies will be well prepared for the tightening energy codes that are spreading across the country. California’s 2020 mandate is just the beginning, and net-zero certification programs are already influencing building codes in other states. The construction methods and design principles demonstrated at Sierra Crest provide a proven template for achieving high-performance residential construction at a scale and price point that works for the mainstream housing market.