What the session was about, according to our live attendees

During the webinar, attendees learned about the significant attention to detail and coordination required to build truly sustainable, high-performance homes, such as those aiming for Passive House (PHIUS), Net Zero, or LEED certifications. Presenters emphasized that achieving these standards often involves innovative approaches to foundations—such as wood-based or concrete- and foam-free options—advanced air sealing, and meticulous design to ensure efficient air flow and circulation. The importance of early and thorough collaboration with raters and contractors was highlighted to avoid costly rework and ensure compliance. The session also covered how building orientation, window selection (including quadruple-pane and variable SHGC windows), and all-electric systems powered by on-site solar contribute to net-zero operational energy and low embodied carbon. Attendees reported learning about several new technologies and construction methods, such as quadruple-pane krypton windows, remote compressor water heaters, and the use of recycled glass material (Glavel) as an insulation or structural base. Many were exposed for the first time to the concept of slabless or wood foundations, climate adhesive products, and the need to manage air stratification in tightly sealed, energy-efficient homes. The webinar also showcased innovative products like wood fiber insulation, super stretchy sealants, and best practices for fresh air intake and HVAC design. Overall, participants appreciated the practical insights, product information, and real-world lessons shared, particularly from the detailed virtual home tour and the experiences of the project team.Please note this project is for sale, and you can learn more about that here if you are interested in living net positive in West MI.

This home is for sale, so learn more here if you want to live Net Positive in West MI!

Article Based on Webinar*

This article provides a comprehensive exploration of the MI Net01 Triple Certified Home with Low Embodied Carbon in Grand Rapids, Michigan. The project demonstrates the integration of Passive House principles, advanced energy and water efficiency, reduced embodied carbon, durability, and resilient design. It also highlights key technical strategies and lessons learned, offering practical guidance for housing professionals, builders, contractors, and an interested general audience. The discussion focuses on how high-performance homes can be designed and constructed to meet evolving sustainability goals, while balancing technical rigor with real-world constraints.

Introduction

The journey toward truly sustainable housing is marked by innovation, collaboration, and a commitment to measurable outcomes. The MI Net01 Triple Certified Home in Grand Rapids, Michigan, stands as a model of such progress. Triple certified under Passive House US (PHIUS), ENERGY STAR, and the Green Star Homes Platinum level, and submitted for LEED Platinum, this residence exemplifies the next generation of high-performance, low-carbon homes. Its development offers actionable insights for housing professionals, builders, contractors, and anyone interested in the future of sustainable living.

Project Overview and Certification Pathways

At the heart of the project’s success is an integrated approach to certification. The home achieves PHIUS Source Zero certification, which requires rigorous energy modeling, construction quality assurance, and operational efficiency. By pursuing PHIUS, the project automatically engaged with ENERGY STAR and Zero Energy Ready Home requirements, ensuring a robust baseline of building performance. The home’s HERS Index rating of -28, compared to typical code-built homes scoring 55–65, sharply illustrates its dramatically reduced energy demand and net positive energy production.

The Green Star Homes Platinum certification further recognizes the home’s achievements in energy, water, health, resilience, and electrification. The pursuit of LEED Platinum underscores the comprehensive nature of the project, with third-party verification at every stage.

Design Goals and Philosophy

The project was guided by four primary objectives:

1. Achieve net-zero operational energy, including the capacity to power two electric vehicles daily.
2. Significantly reduce embodied carbon through thoughtful material selection and innovative construction techniques.
3. Create a home that is “lagom”—not too little, not too much, but just right—emphasizing comfort, durability, and ecological landscaping.
4. Ensure resilience against climate risks, including wind, heat, cold, and moisture, while prioritizing occupant health and long-term durability.

Net-Zero Operational Energy

Achieving net-zero energy performance required a holistic systems approach. The home’s solar photovoltaic array is sized not just for household electricity, but also for two electric vehicles, each driving an estimated 33 miles per day. The roof pitch was optimized (12:12) for maximum winter solar gain, supporting heating loads at times of peak demand.

Passive solar design was carefully employed, with south-facing windows protected by overhangs and porches to manage seasonal solar gain. The building envelope was engineered to minimize heat loss, with a focus on airtightness, high-performance insulation, and advanced window technology. These measures not only reduce energy use, but also contribute to exceptional occupant comfort and quietness.

Embodied Carbon Reduction

A notable aspect of the project is its commitment to reducing embodied carbon—the greenhouse gas emissions associated with materials and construction. The home avoids high-carbon materials such as foam insulation and concrete wherever possible. Instead, it features a pioneering concrete-free, foam-free foundation using wood footings and foam glass aggregate made from recycled glass. This system provides both insulation and drainage, and demonstrates a replicable, code-compliant alternative to conventional slabs.

Above grade, the building envelope employs Timber HP wood-fiber insulation, which not only reduces embodied carbon but also sequesters carbon within the building assembly. The use of durable, low-maintenance siding and roofing further minimizes the structure’s long-term carbon footprint.

Overall, the embodied carbon calculation for the home’s envelope shows a reduction of nearly 60% compared to a conventional build, translating to savings of approximately 35 metric tons of CO2 equivalent.

Durability, Resilience, and Health

The home is designed to withstand climate extremes, including heavy winds, extreme temperatures, and potential flooding. Premium materials, such as a standing seam metal roof with a 60-year life expectancy, and robust water management strategies, contribute to longevity.

A climate-resilient adhesive was used throughout the structure to enhance wind resistance and structural integrity. The double-wall assembly, detailed air and vapor barriers, and continuous insulation create a building envelope that maintains comfort without mechanical systems for extended periods, even during power outages.

The project’s approach to indoor air quality is equally rigorous. A dedicated energy recovery ventilation (ERV) system supplies continuous fresh air, with filtration capable of removing wildfire smoke and volatile organic compounds (VOCs). All construction materials were selected for low emissions, and air quality monitoring is built into the home’s operations.

Water Efficiency and Management

Water conservation was addressed through efficient fixtures, native landscaping (including a rain garden), and advanced filtration. The home achieved an 8 out of 10 on the Green Star water score, reflecting both conservation and quality. A heat pump water heater with CO2 refrigerant (Sanco) was installed for domestic hot water, further reducing energy use and environmental impact.

Construction Innovations and Lessons Learned

Foundation and Envelope

The concrete-free, foam-free foundation is a standout feature, utilizing a shallow frost-protected assembly with foam glass aggregate, Stego vapor barrier, and wood footings. This system, while innovative, required careful coordination with local inspectors and iterative design development. The walls employ a double-stud assembly, with dense-packed wood-fiber insulation and intelligent vapor control membranes (Intello) that respond dynamically to humidity conditions.

Windows and Glazing

High-performance quad-pane, tilt-turn windows were specified to meet the exacting winter heating demand modeled for the project. Window placement and solar heat gain coefficients were optimized for seasonal performance, with attention to minimizing thermal bridging and maximizing airtightness. The windows are mounted using specialized over-insulation techniques to further reduce energy losses.

Ventilation and HVAC

A single mini-split heat pump provides space heating and cooling, supported by the ERV for distribution. However, the project revealed that relying solely on the ERV for heat distribution can result in temperature stratification. To address this, a supplemental air mixing system with quiet, efficient plenum fans was installed, ensuring even temperatures throughout the home. This lesson emphasizes the importance of active air circulation in super-insulated, airtight homes.

Monitoring and Controls

The home is extensively monitored, with real-time energy, water, and air quality data accessible to both the builder and future occupants. Battery storage, EV charging, and solar production are integrated, providing grid resilience and empowering occupants to manage their resource use.

Certification and Quality Assurance

Third-party verification was integral to the project’s success. Each certification—PHIUS, ENERGY STAR, Green Star, and LEED—involved detailed design review, mid-construction inspections, and final performance testing. The home achieved exceptional blower door test results, with air leakage rates well below even the stringent Passive House requirements. Verification extended to insulation density, mechanical system balancing, and documentation of all material and installation details.

Cost, Scalability, and Market Realities

While the home demonstrates what is technically possible, it also highlights the challenges of cost and scalability. Premium materials, advanced assemblies, and extensive verification can increase upfront costs beyond typical market expectations, particularly for first-time high-performance projects. Site-specific factors, such as lot topography and local labor markets, further influence final costs.

The project team acknowledges that future iterations can achieve similar or improved performance at lower cost through design simplification, more standard lot selection, and value engineering. As verification and embodied carbon accounting become more streamlined and integrated into mainstream practices, these techniques can become increasingly accessible to a broader segment of the housing industry.

Practical Guidance for Builders and Professionals

For those seeking to replicate or adapt these strategies, several key recommendations emerge:

• Engage all certification and verification partners early in the design process to identify and resolve potential issues before construction.
• Prioritize integrated design, where architects, engineers, builders, and verifiers collaborate from concept through completion.
• Invest in quality control, especially regarding air sealing, insulation installation, and moisture management.
• Consider innovative foundation and envelope assemblies as alternatives to conventional, high-carbon systems—while maintaining code compliance and local inspector engagement.
• Specify high-performance windows and pay careful attention to their installation details to minimize thermal bridging and air leakage.
• Plan for active air mixing or distribution, particularly in homes with a single-point heat pump and high levels of insulation/airtightness.
• Use real-time monitoring to validate performance and inform future projects.

Conclusion

The MI Net01 Triple Certified Home presents a compelling case for the future of sustainable housing. Through a relentless focus on performance, verification, and continuous improvement, the project team has created a home that sets new benchmarks for energy, carbon, durability, and occupant health. While some aspects represent the leading edge of current practice, many strategies are immediately transferable to new builds and retrofits alike.

The project demonstrates that ambitious sustainability goals are achievable with careful planning, collaboration, and a willingness to innovate. As embodied carbon accounting, electrification, and resilience become mainstream, the lessons from this project will inform the next generation of high-performance buildings.

Key Takeaways

• Integrating multiple certifications (PHIUS, ENERGY STAR, Green Star, LEED) ensures comprehensive performance and quality assurance.
• Passive House principles deliver exceptional energy efficiency, comfort, and resilience, but require meticulous design and construction.
• Innovative concrete-free, foam-free foundation systems can dramatically reduce embodied carbon while maintaining performance and code compliance.
• Material selection, particularly wood-fiber insulation and durable cladding/roofing, is critical to long-term carbon and maintenance outcomes.
• High-performance windows and airtight construction are essential for minimizing energy use and maximizing occupant comfort.
• Active air mixing or distribution is necessary in super-insulated homes to prevent temperature stratification.
• Real-time monitoring of energy, water, and air quality supports ongoing performance validation and occupant health.
• Early and integrated collaboration among architects, builders, contractors, and verifiers is essential to project success.
• While premium performance can increase costs, many techniques are scalable and will become more affordable as the market evolves.
• Embodied carbon accounting is an emerging field; streamlined tools and integration with energy modeling will support broader adoption.

Here’s a detailed Q&A write-up based on the provided questions and the speaker’s answers:

Yes, PV array was sized to power the house and two EVs at 33 mile/day each, assuming 3 miles/kWh which is the USA average. This adds up to just over 4 MWH/EV/year.So roughly speaking, the PV array is sized to provide 8 MWh/year for the EVs and 7 MWh/year for the house. It takes a lot of power to move vehicles down the road!

Note that the PV array is 32 panels totaling 12.48 kWp. On the 12/12 south- facing roof, with modest shading, it is modeled to produce just over 15 MWh/year.Also note that the utilities in Michigan allow for 4.25 MWh/EV charger/year for new construction array sizing and interconnection approval.

Costs sunk into the house including the lot, architectural fees, certification fees, materials, subcontractors, employee labor, Dale’s direct labor, and the cost of money total ~$1619K. Credits including material and utility rebates and the Federal Investment Tax Credit totaled ~$56K. Therefore net costs total ~$1563K. A 7% project markup puts the asking price at ~$1678K.

The metal roof was custom roll-formed to length on site by https://buistsheetmetal.com/ using 17” 24ga panels from Drexel 

Interesting that Alpen is no longer shipping the windows with pressure-equalizing bags, but is instead charging them with the right amount of gas for the final location.

This will save site labor, thank you.For more details on the concrete-free and foam-free foundation and envelope, see these two JLC articles: https://www.jlconline.com/author/dale-hulst/

For more information on Climate Adhesive: https://climateadhesive.com/

I was aware that Holcim Cement was working on eco mixes but could not get contractors or redi-mix places in town to send me data. It seems it might be available now per this AI search? If so, that is good! I will chase again next time. (If there is a gap between what is possible and what is practical for one residential project, perhaps a group of eco-committed contractors could work with a local redi-mix plant to offer eco- mixes, say, one day a week?)The final blower door pressurization/depressurization average was 157 CFM = 0.0282 CFM50/ft2 which is less than half of the Phius requirement of 0.06 CFM50ft2 of envelope. This converts to ~0.60 ACH50.

Windows used were Alpen Tyrol quad pane (thinglass for the inside two panes). I see the frames have been redesigned a bit since I bought the ones at the house. Here’s alink to the current version: https://www.thinkalpen.com/tyrol-residential-upvc-windows

Low carbon materials were difficult to find. I would always ask for low carbon products (net zero if possible) that were also healthy (red list free). If there were some options I would also ask for EPDs. It is a time-consuming process that involves trying to get good data and not just good marketing. I’m proud of many of the materials we chose…and still had some that are imperfect. You can see many of the materials chosen in the Matterport virtual 3D tour on the pins.

About appraisals, my understanding is that the bank will have one done when a potential buyer goes to them for a loan. Their appraiser may know very little about high performance/green construction and therefore undervalue the house. Therefore I was considering hiring someone with experience appraising high performance houses with solar so I would have my own independent assessment. They would use a document called the “green addendum” which lists all the energy saving features and certifications.

I filled one out just to see how it worked; see attached.

Batteries are Enphase 5P which are lithium iron phosphate = safer chemistry than lithium NMC. https://enphase.com/store/storage/gen3/iq-battery-5p

Details on the windows:Header Details Jamb detail:Sill detail