Which brings us to “The Truchas Earthship,” a net zero, passive solar home in the Greater World Community, a sustainable development on 640 acres of natural habitat preserve in Tres Piedras, New Mexico.
The Earthship incorporates natural and reclaimed materials in its construction: The main building blocks are recycled automobile tires that have been reclaimed through a partnership with the local landfill. Other repurposed products such as glass bottles, aluminum cans, plastic bottles and cardboard are used in the structure’s walls, doorways and elsewhere. Locally sourced lumber and other building materials are utilized in the construction.
Name: Truchas Earthship, Tres Piedras, New Mexico
Builder: Earthship Biotecture
Architect/Designer: Michael Reynolds, Earthship Biotecture,
Photographer: Meredith Albury, Earthship Biotecture
It’s par for the course. “I’ve responded, over a period of 50 years, to the problems of civilization on this planet,” Reynolds says. “I’ve incorporated my own solutions, trying to make a building that would be appropriate and responsive to the modern day issues of climate change, overpopulation, and dwindling resources.”
The Earthship’s heating and cooling functions are provided through passive solar and natural ventilation strategies, without electric heat or the use of fossil fuels. Windows have floor to ceiling glazing; all of them face south.
The north, east, and west walls are surrounded by a dirt berm. Tire walls act as a large mass and hold the heat in when the sun shines on them. And, insulation prevents cool air from getting in and the warmth from escaping.
In winter, the sun enters through skylight glass and heats up the mass of the floors and walls. In the summer, with the sun high in the sky, the building stays cool with the constant temperature of the earth. Cooling is provided with natural ventilation through buried cooling tubes and operable vent boxes.
The cooling tube is a corrugated metal tube near the bottom of the wall and goes through the back berm of dirt. Cool air comes in through that tube. Hot air is pushed out of the skylights as the heat rises.
A 2.5 kilowatt solar array attached to the south facade of the structure provides electricity within the home. Effectively, the building has its own “renewable power plant” with photovoltaic panels, batteries, charge controller, and inverter, Reynolds notes.
All water for use within the structure is provided by a catchment system on the roof. The system is supported by inground, insulated cisterns that feed the water into the building via gravity, to be processed by an interior water management system manufactured by Earthship Biotecture.
Plants treat the water until it’s clean enough to be collected in a well at the end of the planter and pumped, on demand, to the toilet tank for flushing.
The Earthship also features a 690-square-foot interior double greenhouse at the south side of the building for in-home, organic food production. An exterior septic system and leach field provide the final processing of blackwater to be utilized to feed and nourish exterior landscaping in the high desert climate.
In terms of being a green home, the Earthship is a pretty complete package. As a result, the home was named winner of Green Builder’s 2023 Green Home of the Year (GHOTY) competition, in the Alternative Building category.
“[The project] addresses all space heating and cooling needs via passive solar with thermal mass design, and all plug loads with solar [photovoltaic] and batteries,” says GHOTY judge Theresa Gilbride, a building energy efficiency researcher at Pacific Northwest National Laboratory in Richland, Was. “Also, the extensive use of recycled materials may mean lower upfront cost if labor is reasonable.”
Alternative Building Systems: Solar power system, thermal solar heating and cooling system, rainwater catchment system, on-site sewage treatment system, indoor food production system, and use of 45 percent recycled materials, including used automobile tires, aluminum cans, glass bottles, cardboard, and plastics.
Appliances: All standard, running off solar system
Building Envelope: Earth-rammed automobile tires forming thermal mass, insulated on the exterior with R-45 polystyrene and R-80 polystyrene in the roof
Caulks and Sealants: Dap Alex Plus
Electrical: Power Organizing Module – lithium iron batteries; Schneider Electric inverter, Schneider Electric Charge Controller; solar panels
Exterior Finishes: Standard adobe plaster
Flooring: Flagstone and tile
Furniture: Handpicked and refurbished second-hand furnishings and heirlooms
HVAC/Ducts: Natural convection via cooling tubes and skylights
Insulation: R-80 polystyrene in the roof and R-45 polystyrene surrounding the walls
Lighting: LED lights
Paints and Stains: Alize, a natural clay based paint that is made in-house.
Pavers: Flagstone
Plumbing/Plumbing Fixtures: Standard toilets and sinks
Renewable Energy Systems (solar, wind, etc.): Solar Roof: Precision Roofing Pro-panel Metal
Specialty Products: Stained glass achieved with colorful bottle bricks, made in-house; Interior, non-load bearing aluminum can walls encased in adobe plaster and cement plaster
Structural Components: Automobile tires used in a three-foot compression mass wall
Ventilation: Natural convection with Earth tubes and skylights
Water Filtration: Water Organizing Module – 50 micron filter, 500 mesh filter, 1,000 mesh filter; D/C aquatic pump; Doulton High Flow Ceramic Water Filter Amtrol water pressure tank
Water Heating: Solar hot water heater, with a Rinnai propane-demand backup water heater
Other: Food production in the greenhouse, including bananas, fig trees, and rosemary
As we move from one major lifestyle challenge—an emergent pandemic—to another, with historic storms and record heat, builders have been continuously challenged to adapt. Green Builder’s 2023 Green Home of the Year winners are well constructed, energy efficient and creatively designed. But our grand winner topped them all by emphasizing the local economy and the environment.
Our expert panel of judges evaluated projects in terms of overall sustainability, resilience, synergy with the environment, affordability, creativity and the depth of science employed.