California is officially “ready” for its first zero carbon homes.
The first of four single family homes in Marisol Malibu’s new zero series in Malibu, CA has achieved Zero Carbon Ready status through the International Living Future Institute (ILFI) and is on track to become the first Zero Carbon Certified building in California.
Brought on early in the project as the Zero Carbon Consultant, Stok led the Zero Carbon Certification effort in full and collaborated closely with the ILFI to create a first-of-its-kind Zero Carbon Ready pathway to achieve the developer’s goals.
Here we introduce the new Zero Carbon Ready pathway, as well as the specific strategies Marisol Malibu took to not only achieve this status, but also become embodied carbon negative without carbon offsets—a major accomplishment that sets a new standard for zero carbon real estate.
ZERO CARBON READY: A NEW PATHWAY
While 12 months of occupancy data is required for full Zero Carbon Certification, developers will often want to demonstrate their sustainability achievements to prospective buyers/tenants earlier on. Identifying this missing alignment between selling and certification timelines, Stok helped create a new ILFI standard: Zero Carbon Ready.
To do this, Stok reviewed the ILFI’s existing Zero Carbon Certification, outlined what would be included in the “Ready” pathway vs “Final” pathway, then implemented it on the project with approval from the ILFI.
“In pursuit of our goal to create the greenest buildings for a healthy world, ILFI Zero Carbon Certification verifies carbon neutrality for both operational and embodied emissions. Stok’s deep knowledge of ILFI’s programs and proactive approach has helped us expand the reach and impact of our programs, accelerating action on climate change in homes and commercial buildings around the world.”
–Haley Gardner, Manager, Energy + Carbon, International Living Future Institute
The Zero Carbon Ready pathway is now a public standard available to any project pursuing Zero Carbon Certification, including commercial developments. Like the USGBC’s LEED pre-certification and IWBI’s WELL pre-certification, it allows projects to market their zero carbon status without the wait, with a plan to verify performance in the following 12 months.
EMBODIED CARBON NEGATIVE… WITH ZERO OFFSETS
Stok also did an embodied carbon dive including a thorough material analysis, structural design recommendations, sourcing recommendations, and a comprehensive Whole Building LCA of all materials. This deep analysis helped the project get to embodied carbon negative without any offsets. This incredibly unique accomplishment demonstrates that not only is carbon negative real estate possible, but carbon negative real estate without offsets should be our true vision for the future.
“With Stok’s help, we are nearly finished with what will be ILFI’s first Zero Carbon Ready project in the world. Stok, with its world-leading perspective on embodied carbon reduction practices and expertise with LCAs, has allowed us to build a carbon sink—with a net of -140 metric tons of embodied carbon. We couldn’t have done it without them!”
–Scott Morris, Developer and Director of Carbon Sequestration, Marisol Malibu
Overall, the project resulted in 618 tCO2e of embodied carbon emissions while sequestering 758 tCO2e through the biogenic carbon of sustainable timber, resulting in -140 tCO2e net emissions.
ZERO CARBON STRATEGIES: EMBODIED & OPERATIONAL
Marisol Malibu implemented significant embodied and operational carbon reduction strategies to achieve Zero Carbon Ready status, including the following specific efforts.
Embodied Carbon Reduction Strategies
• Sustainable Timber: Timber used on the project was handpicked to ensure sustainability. Preference was given to local lumber from California forests, prioritizing lumber from uneven-age managed forests first and 17.5 acre even-age stands with some retention second. The second preference was given to FSC-certified lumber from Oregon and Washington. Where FSC was not available, conventional lumber was used. Over 95% of the wood met this sustainability criteria.
• Raised floor timber foundation: Used in lieu of a traditional post-tension slab concrete foundation.
• Hybrid Framing: Structural steel replaced with timber (glulam) where possible.
• Steel: Sourced from the US, manufactured in electric-arc furnaces (with no direct emissions), and selected with the greatest recycled content available.
• Rebar: Sourced from the Nucor Seattle plant, which manufactures the lowest carbon rebar in the US.
• Concrete: Had 25% of cement replaced with recycled material.
• Insulation: Used primarily high-density cellulose insulation, some mineral wool, and fiberglass in lieu of majority mineral wool and fiberglass, traditional rigid XPS insulation, and foam.
• Gypsum Board: Selected USG EcoSmart gypsum board due to low carbon properties and replaced a majority of 5/8” with 1/2” to minimize material.
• Roof: Selected standing seam aluminum roof with 99% recycled content (76% post-consumer) from Jupiter Aluminum, which manufactures the highest recycled content coil in the US.
Operational Carbon Reduction Strategies
• All-Electric: The home does not use any fossil fuel energy sources.
• Solar Power: 18.7 kW PV solar array provides enough energy to power the home.
• 100% Renewable Grid: In case the solar array underperforms, the home will receive 100% renewable energy through the Clean Power Alliance.
• Battery: Tesla Powerwall units provide energy backup.
• Mechanical Systems: SpacePak hydronic heat pump system distributes energy by way of heated and chilled water throughout the home, which is more efficient than transporting air. Ducts are kept short to increase efficiency and air recirculation includes highly-effective MERV13 filtration.
• Ventilation: Dedicated Zehnder outside air 24/7 ventilation system provides fresh air with heat recovery while conventional bath fans operate intermittently to quickly remove excess moisture from bathrooms. The two systems together maintain high indoor air quality.
• Enclosure: Insulation levels meet the exceptionally stringent 2016 California Energy Code.
• Water Heating: The Sanden hot water heat pump uses CO2 as refrigerant to heat the water, which has a global warming potential 2,088 times less than conventional R-410A refrigerant.
• Pool Heating: Used AquaCal electric heat pumps in lieu of traditional fossil fuel (propane) systems.
• Electric Fireplace: Used Nero Fire Design water vapor fireplace.
Whether you’re working on a single family home or commercial portfolio, these embodied and operational carbon reduction strategies can be applicable to your project. Reach out to Stok to learn more and explore the Zero Carbon Ready pathway.