Earthships in New Mexico

In mid-February we visited Taos in northern New Mexico. The area is named for the indigenous Taos Pueblo who have lived beneath the mountain here since time began (according to oral tradition--Western historians suggest 1,000-years). Unfortunately, Taos Pueblo is annually closed to visitors during February, so we missed out on seeing their multi-story adobe variation on 'sustainable design.' Nevertheless, we did drive north a few hours from Santa Fe to tour some ‘Earthships’ west of Taos. This also meant braving the long, narrow, bouncy Rio Grande Gorge Bridge ("7th-highest in the U.S.") and later wandering out onto it (see photos far far below).

Mike Reynolds founded Earthship Biotecture in 1992, although he's been working on sustainable architectural design since the ‘60s. Looking north from the Welcome Center (photo above), there are multiple distinctive, one-story, glass-faced buildings for as far as the eye can see. The buildings skirt the western canyon of the Rio Grande Gorge. Reynolds now runs an academy here where you can learn to build your own earthship, and while there’s no formal association among the buildings within sight, the remarkable uniformity makes clear that most of the locals mixed their kool-aid at the same watering hole.

Our tour-guide James shows us down the hill into one of the first earthships ever built, which is now used as a classroom. He tells us he himself bought an already constructed earthship 9-years ago, and more recently, he’s moved in to live there full-time. He makes clear that they’re not for everyone as their various systems require specific knowledge and maintenance. As their website succinctly describes, "An Earthship is a type of passive solar house that is made of both natural and upcycled materials. Several models exist, and can be built in any part of the world, in any climate and provide electricity, potable water, contained sewage treatment and sustainable food production.” So James begins to explain the basic principles of earthships to us — broken down into six general categories: Natural & Recycled Materials, Thermal Heating & Cooling, Renewable Energy, Water Harvesting, Food Production, Black Water Treatment.

Thermal heat & Cool

First is passive solar design. ‘Passive solar’ is a technical term for ‘facing the southern sun;’ it’s why buildings to the north outside look so uniform, which initially struck me so comically. All these structures (including the one we’re sitting in now) face directly south, and today’s mid-winter February sunlight streaming through the front windows provides the building’s primary heating. The ambient earth that forms the north wall maintains a fairly steady temperature inside the house between 55-58 degrees Fahrenheit (i.e. warm in winter, cool for summer), and James tells us his place is usually in the 60s when he wakes up on winter mornings. Which is pretty impressive to us, as in February, the outside temperatures in this high-desert are still dipping into the 20s and 30s at night.

Whereas in the summer, the sun will be considerably higher in the sky, directing little to no sun through these front-windows, and James showed us the ‘AC’ — a PVC pipe that runs through the rammed-earth berm into the earth. While a simple hinged panel shuts it during the winter, the natural circulation of heat during the summer pulls the cool from the subterranean earth through the earthship’s open space.

Due to the abundance of sunshine in the desert, solar panels on the roof produce enough energy to heat the water tank and provide electricity for pumps and lights and etc.

Up-cycled materials

Early on in our tour, our guide James showed us a 'brick' Mike Reynolds designed from a beercan back in the 60s. Recycled industrial materials such as these (or used tires) are what distinguishes earthships from, say, Taos Pueblo's millenial adobe homes. James openly acknowledged that earthships integrate multiple sustainable technologies developed previously--such as water cachement, rammed earth, passive solar heating, as well as more modern technologies like solar- and wind-generated electricity.

An earthship's basic design begins with a berm of rammed-earth, which effectively acts as the structure's thermal battery. Walls of about 2.5-3ft thickness are built around used car-tires, which are firmly packed with earth and stacked on top of each other. As James mentioned a few times throughout our tour, the biggest cost of building an earthship isn’t from materials but from labor. Apparently compacting earth into tires takes a lot of elbow grease! Naturally, more hands make less work. & the resultant structure is truly built to last. They somewhat resemble castles in the desert.

Water Harvesting & Distribution

The roof is built on a slope to harness rain through a scupper (that's a nautical term for a rough open-air drain), which filters water initially into a cistern situated inside the berm and above a pump. A silt catch of gravel filters the water initially and requires maintenance every 6-months to a year. The second filter contains 60-holes and uses a DC or AC pump to pressurize the water to 40-60 PSI. Thirdly, a mesh 500-hole filter purifies the water even further, and blocks out particulates 50-microns or more; this produces clean water, which is, however, not yet potable. Lastly, a fourth mesh 1000-hole filter designed for 30-microns of particulate matter produces potable water. These finer filters do need replacing every year and a half. So, each sink includes multiple taps for water — a drinking-water tap and a grey-water tap, which is adequate to wash dishes, for example, or wash your hands.

At nearly 7,000ft above sea-level, Taos is classified as high-desert. Typically there's not much precipitation (5-10"/year), and we had already heard anecdotally from locals that there had not been much snow (& as of this writing, most of the area remains in Extreme Drought conditions). NB, all these climatic details become extraordinarily important when your house's water supply depends on yearly rainfall. Despite that, James said that he hadn't hauled water to his place in years. His cistern has the capacity for 5,000 Gallons.

This climatic factor clearly elevates the importance of clean water. After filtering it so meticulously, why would it be used to wash dishes or flush toilets? So as touched on above, the design creates a hierarchy of water usage as at sinks — where multiple uses suggest two faucets. Recycled, grey-water is redirected to run through the greenhouses, and it’s also used to refill toilets. Black water, which is the technical term for dirty, semi-toxic water, is lastly filtered out through tree roots. The roots benefit from the moisture and assist in filtering sewage. In such desert conditions, it’s impressive to see how many ways water can be used and re-used.

Greenhouse

The greenhouse was one of the newer features to be built into the earthship model. Fairly intuitively, it sits in the windows up front and uses grey-water from the rest of the house. Once again—in mid-February, we were wowed simply to see such thriving greenery, which included practical plants such as tomatoes and nasturtium as well as begonias, ferns, flowers and several deciduous fruit trees (which were in winter mode). While a relatively recent addition, the greenhouse model poses a further element of self-determination and interdependence inside the earthship’s ecosystem.

Thanks to James (@ the Hermit Mechanic) for his knowledgeable tour, and obviously we recommend a visit if you’re ever in the Taos area.