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Building/Project Details

Building/Project NameGreen Idea House Construction / refurbishment date30/10/2017 Building/Project Size199.7 sqm
Building/Project Typeresidential single Address 1556 Prospect Avenue Hermosa Beach California 90254 United States Region americas

Performance Details

Net Zero Operational Carbon

Buildings or developments that are verified and certified as “net zero operational energy and/or carbon.” The building should demonstrate the highest levels of energy efficiency with the use of either renewables generated onsite or renewable energy procured offsite.

Achieved Certification Scheme: ILFI Zero Energy
Energy Use Intensity (EUI) (kWh/m2/yr): 51.6 Onsite Renewable Production Intensity (RPI) (kWh/m2/yr): 53.7 Verification Year: 2018

Tell us your story

In 2002, the owners noticed soot accumulating outside their newborn son’s bedroom window. On that day, their ambition to convert their 1959 Hermosa Beach house to an economical, carbon-emission-free, zero-net-energy home was born. Ten years later, the family moved back into a remodeled upgraded home, 800 square feet larger than the original. While the project had then not been entirely completed, the family was already enjoying harvesting all of the energy they needed from their rooftop solar panels, and sending 80 kilowatts back to the grid each month. But the remodel went beyond the typical energy upgrade, the home is entirely electric and features numerous other green strategies including:

FSC Certified Lumber

The structure used advanced framing, and where possible, lumber certified by the Forest Stewardship Council.

Local, Recycled, Reused Materials

The living room ceiling is made from 80-year-old redwood salvaged from a structure in Los Angeles. Recycled permeable Stepstone pavers create a path from the driveway to the stairs, and recycled tiles from Oceanside Glass and Stonepeak are used in the interior.

Recycle/Reuse of Demolition Waste

The project was able to recycle 97.5% of the demolition waste and incorporate salvaged materials through thoughtful deconstruction by the Reuse People and RER. Lumber from the existing home was used in the remodel, and broken-up patio material was repurposed into backyard garden walls. Materials that could not be used in the project found new homes via internet and newspaper ads.

Rainwater Harvesting

Rainwater is captured in a 1,200-gallon Norwesco tank, where it is stored for use on the landscape.

Air Sealing

Attention to both airtight materials and air sealing details during the remodel led to an 80% reduction in air leakage. This translates to a significant reduction in both unintentional entry of outside air and loss of conditioned interior air.

Giving Back to the Community

The owners have used the Green Idea House as an opportunity to engage and educate the community about green building. Work crews from Youthbuild, a non-profit organization that teaches trade skills to at-risk inner-city teens, helped deconstruct and install portions of the project. In addition, the family has opened the house for many tours and shares their story on

The owners’ objective was to achieve net zero energy with zero carbon – that is, to harvest more renewable energy than they consumed on an annual basis.

“We liked the simplicity of the definition. We did a series of design charrettes that paid close attention to materials, waste, energy, water, and toxicity. We capped off the gas line, which was seen as radical back then (2002), and none of the energy models that were done at the time could fully capture what we were attempting to do. The building turned out to work far better than predicted We ended up diverting 97% of the demo and construction waste and reducing our water bill by about 1/3. On the energy side, we over-generate enough to cover our two electric cars.

The trick to getting the project to cost less was to think of the problem more holistically. For example, if the overhangs, insulation, and air sealing could help heat and cool the building naturally, their incremental cost would be more than offset by the smaller mechanical heating and cooling systems that would need to be installed. That does not even contemplate the operational costs over the life of the building. Also, we partnered with over 70 public and private entities on the project (see Partners page on the We very rigorously vetted their products and gave them feedback on their sustainability features. Some partners donated products or gave a discount in exchange for cross promotion with our project.”

Renewable Production Systems Information

Photovoltaic solar panels – At a cost of $18,000 after rebates, 26 photovoltaic solar panels with the capacity to produce 6.5 kW of electricity were installed on the rooftop by Mediterranean Solar. The array is oriented to the southwest and incorporates Enphase micro inverters. The panels were manufactured in the United States by SolarWold Panels. At the end of the panels’ 40-year life, the manufacturer commits to removing the silica from the panels and recycling them.

Find out more about this case study from ILFI here.

Submitter's Details

OrganisationInternational Living Future Institution

The owners’ objective was to achieve net zero energy with zero carbon – that is, to harvest more renewable energy than they consumed on an annual basis.