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Life in an earthship

These fully sustainable, off-the-grid dwellings can maintain a comfortable interior temperature regardless of the heat or cold outside. Photos: Home sweet earthship

TAOS, N.M.--Imagine maintaining a steady 70 degrees in your house high in the New Mexico desert, even as outside temperatures vary between 100 and minus-20, all without spending a dime on power.

Can't picture it? Owners of an innovative type of housing known as earthships can.

That's because earthships are specifically designed to be comfortable in any climate even as they're entirely off the grid and made using a healthy supply of natural and recycled materials.

Earthships currently exist in every U.S. state and in several other countries, but the Earthship World Community, about 15 miles northwest of Taos, N.M., is ground zero for this alternative form of dwelling. It's forbidding country: flat, arid, high-altitude and really hot in summer. And really cold in winter.

As you head west on U.S. Highway 64, you come across a collection of about 60 oddly shaped but wonderful-looking houses off the right side of the road. And you immediately notice one thing: each and every one of them is built into the side of a small hill.

But it's not just any hill. It's a south-facing hill. That's crucial, because it means each earthship has its major windows facing south. And anyone who's ever put a minute of thought into the way their house is oriented knows that facing south means being directed toward the most sunlight--in the northern hemisphere, anyway.

And this is one of the keys to the whole concept: sunlight, and lots of it.

I learned all of this when I visited the earthship headquarters during Road Trip 2007, my journey around the Southwest in search of the most interesting science- and technology-related destinations.

The word "earthship," my host Kirsten Jacobsen told me, comes from the houses being in and of the earth--that is, made of earthen materials and built into the ground. The term also refers to the experience of living in a ship, which requires dwellers to be autonomous from outside help.

Jacobsen then explained the six major points that define the earthship philosophy: thermal solar heating and cooling; building with natural and recycled materials; using electricity only from solar and wind; harvesting water from rain and snow; on-site sewage treatment and containment; and the last, and most recent development, producing food in the house itself.

The keys to the system's success are the south-facing windows and solar arrays; walls made from materials that store heat, such as stone, dirt-filled tires and adobe blocks; and a natural ventilation system. These factors work together with the natural temperature of the ground, and with the sun and the seasons, to heat and cool the house without ever requiring air conditioning or heating. Plus, construction is geared toward circulating air throughout the dwelling.

I had been intrigued since I read about earthships in my Southwest guidebook, which said almost nothing about them except there was a community of people living in off-the-grid houses built into the ground. So I didn't know exactly what to expect.

I had no idea, for example, that many of the earthships would be beautiful exercises in aesthetic architectural design. Or that having a greenhouse in your living room could be a livable scenario, let alone a crucial one.

Even if I had known those things, based on what the guidebook said, I might have expected earthships to be smelly, bug-infested claptrap cabins.

Instead, I saw an elegant, modern, fully appointed home that would have fit in almost any community.

The brand-new, one-bedroom house--which Jacobsen's boyfriend, Ron Sciarrillo, built and is selling for $299,000--has a lovely, airy feel. It's bright inside, and has all the amenities one might expect in a newly constructed house: a full kitchen, washer and dryer, flat-screen TV, Wi-Fi, a regular bathroom, a nice bedroom and more.

And it has internal greenhouses, which, Sciarrillo explained, provide an extra buffer to the sunlight, making a major difference in how the house regulates its temperature.

One secret of an earthship is that in the summer, when the sun is high in the sky, light comes in at a steep angle, meaning the interior isn't flooded with direct light. In the winter, the effect is the opposite: the sun is at a low angle, meaning the interior does get flooded with light all day, while the greenhouse, the floor, the adobe and the hillside construction store heat.

That's why, in hotter climates, rooms would ideally be located deeper within the structure so the sunlight tends to only hit the front end, while in colder climates, you would want shallower rooms, so that more of the rooms would fill with light.

It might be odd to think that a house built in a location that gets only 8 to 10 inches of rain a year could have a full kitchen, flushable toilets and a washing machine.

But the earthships employ a smart water-use system.

The water is collected when it rains and stored in a cistern to be used and reused throughout the house. Water is first used for tasks like washing dishes or clothes, then it's circulated through the house for the greenhouse system, and then for toilet flushing.

A combination of solar power, wind power, DC wiring and high-efficiency DC lighting allows for full electricity in a house with no connection to the grid.

Sciarrillo also explained that if the wiring system is done properly, there should be enough power left over to run AC appliances like TVs and stereos.

To be sure, building an earthship isn't cheap. Sciarrillo said that construction costs average about $175 a square foot, compared with about $125 per square foot for a conventional house. Further, the power generation system runs about $20,000.

But he also said that when you factor in all the recycled and natural materials used in construction--dirt and tires for the load-bearing walls, and glass and plastic bottles, which let light in through non-load-bearing walls--the costs may come closer to those of conventional buildings.

Plus, over time, the savings from being off the grid adds up, though Sciarrillo said it could be 15 to 20 years before they zero-out the costs of the power generation system.

It's also true that building an earthship is a laborious process. For example, each of the many, many tires used in the walls has to have dirt pounded into it manually. The result is a 350-pound brick, but making that takes time.

Of course, you probably can't plop down an earthship in the middle of a city, Sciarrillo said, as building departments may be wary of granting permits for a housing system they're unfamiliar with, and that may go against almost every building concept they know.

But if you want to build somewhere a little more remote, and have the time and energy to spell out the systems to those granting the permits, it could be an ideal solution.

And given that this is a way to have a house that doesn't rely on fossil fuels, is fully sustainable and can be comfortable in any climate, I'm won over. I'm ready to start building.