CHAPTER I: The Myth of Thermal Comfort

In the “Earthship 101” slide presentation, the second slide says, “Imagine… living in a home that cost you nothing to heat or cool…” The problem with this statement is that it is wishful thinking. The base water and power systems required to run Earthships cost $60,000. Systems for heating, cooling, humidity control, and ventilation are required in almost every circumstance, but they are omitted from the Earthship design and therefore budgeting, because the “Earthship controls its own temperatures.” While this is an admirable ideal, it is not accurate, or even physically possible, which we will explain in some detail throughout this book. Regardless, a traditionally-built home’s system for mechanical, electrical, and plumbing costs around $35,000. So in buying an Earthship systems package, the owner has paid a $25,000 premium to “pre-pay” for water and power. The problem is… an owner of a traditionally-built home will spend somewhere around $20,000 over the life of their home to buy water, gas, and electric from utility companies. That means an Earthship owner pays a $5,000 premium over and above what a regular grid-tied user will pay over the lifetime of their home, plus they still need backup heat, additional solar panels and batteries for some locations, as well as humidification controls and cooling in many locations. Furthermore, Earthships commonly use propane for domestic hot water, cooking, and supplementary heating, as well as some form of gas generators for backup power for cloudy days. These are not free and those costs are not factored into the vast majority of budgets. 

Because Earthships are not designed for their specific climate, they tend to have hot and cold spots. The Earthship literature tells us that “the average temperature in an Earthship is 70 degrees.” That sounds really comfortable, right? Except that temperature is based on an average of 365 days. The research and experience of many owners tells us that up to 70% of those days will include extended periods of over and under-heating - an Earthship is often hotter than comfortable between 10am and 7pm in summer and colder than comfortable between 7pm and 9am in winter.

Principles of a solar oven – why Earthships overheat

There is no other way to say it: Earthships, especially those with slanted glass and no overhangs, tend to overheat. Even in the winter. Many Earthship owners will say that even when it is -10°F outside and snow is blowing sideways in 40mph gusts, they will have to open up all the windows to cool their home off enough to be comfortable. That might be okay for a while. However, as we get older, or as our hands cannot crank windows and vents anymore, as we tire of stopping what we are doing to get up to open and close windows twice a day, or when we have to get snow off the windows when its freezing cold… this becomes a relevant maintenance issue.

A substantial amount of scientific research has been done on thermal performance of Earthships in varied American, Australian, and European climates. We will share some overviews of the findings by these researchers later in Chapter 2, but the consensus is that Earthships overheat as much as 9 months a year, depending on location. Earthships also under-heat in northern latitudes due to cloudy conditions, colder inner-earth temperatures, and the fact that earth-sheltering is designed to be used for passive cooling. That means supplementary ventilation, dehumidification, and/or heating need to be considered basic requirements for the Earthship to work. Most of the time, these additional systems are installed after the build, which can lead to unsightly additions that were not accounted for in budgeting. Acknowledging this early allows us to address these issues in the design phase, where we can make the intrusions fit beautifully into the home and plan for the financing to make it all work.

We know now why the buildings overheat, which is great because it means we can do something about it. Earthships, when they use slanted windows and no overhanging roof, are designed like solar ovens. The buildings are oriented to true south, and the slanted windows allow in too much sun. In the summer, the greenhouse can be stiflingly hot and humid. The heat is not quite as sweltering in winter, but neither is it comfortable. The temperature in the greenhouse can be “unbearable” as some owners have stated, swinging between 45°F and 95°F depending on the season. A shade cloth is often required on the greenhouse in the summer to prevent overheating. If we design this critical area correctly from the outset, we do not need that shade cloth and can avoid overheating. 

Many early Earthships did not use wall insulation. This is a problem, even in Taos. Some builders these days are insulating their Earthships, and/or putting a line of insulation as a secondary wall 4 feet outside the tire walls. The extra insulation costs money, uses more unnatural and unsustainable resources, and takes more time to build. Plus, it is yet another system that can fail. The issues that cause the need for these extra materials can be addressed with good design that speaks to your climate.

In the winter, because there are not many windows in the north-side living spaces, the north ends of the rooms stay at or near earth temperature, which is around 58 degrees in Taos, but is much lower in other parts of the world. So you have to have a sweater in part of the house and then strip to your skivvies to pass through the greenhouse to another part of the house, where you will need your sweater again. We also know now that supplemental heat is needed in winter, especially in areas where it freezes. Earthship builders in cold climates who prefer comfortable indoor temperatures are likely to a) install floor and foundation insulation, and b) install a heating system. Foundation insulation is critical because the cold can seep up from the earth and make spaces uncomfortable for anyone not wearing socks and sometimes even insulated winter boots too. Radiant floors, wood stoves, fireplaces and furnaces are all common additions in colder-climate Earthships. 

Even in the winter, non-vented Earthships with the greenhouse open to the living areas can be stiflingly hot. Supposedly, roof venting, and the new earth tubes (which are not able to be retrofitted) helps prevent overheating in the summer. However, this natural ventilation cooling technique only works in areas where humidification is of no concern. In humid or dry areas, we also need to supplement the tube and vent system with dehumidification (in humid areas) or humidification (in arid areas). Otherwise, in a humid environment, an Earthship will collect water along their interior wall surfaces, forming a vertical pool for molds and algaes to grow. This often occurs on the walls of the planting areas and edible plants end up being infected or overwatered. This is an epidemic issue among the many Earthship dwellers who do not live in an environment as arid as Taos.

This is why we discuss both active and passive thermal comfort strategies in this book.

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CHAPTER I: The Myth of “Will Provide You with What You Need to Survive…”

The Earthship greenhouse is not just designed to provide a space to collect natural heat and light from the sun. It is also intended to be used as a greenhouse for growing your own food. The plants in the greenhouse are fed by a greywater system that uses reclaimed shower and sink water to water the plants, which then clean the water for use in toilets later. That is a cool idea! In the Earthship literature and books, it is emphasized that that the Earthship greenhouse can grow “all the food you need to survive.”

Of the people whose Earthships we surveyed, who we interviewed, who commented on blogs or forums, or who answered our surveys… none were able to corroborate this ideal. Certainly the greenhouses can provide some food. But, the people we spoke to said that they could not grow their own food in sufficient supply to say they were provided all they need. They used grocery stores, farmers markets, or CSAs as their primary source of food. The Earthship greenhouse served as a supplemental resource, and only seasonally, in many cases.

An architect who blogs anonymously was in the audience at one of the Earthship lectures in Australia. Afterwards, he reported in his blog that he struggled with the lifestyle and thermal performance data presented, as the presentations implied the information presented was an “undisputed truth” when in fact some of the data presented showed clearly that there were issues with performance. But, people would have to know what to look for in order to determine what parts were concerning. (This is why we attempt to explain the width and breadth of the research in Chapter 2.) He went on to question if the fish or water plants in the pond systems used for aquaponics were edible. He then calculated that in order to eat fish in the recommended dietary amounts of three times a week, you would need to harvest at least 12 fish each month. Clearly that would require a large and sophisticated system, which would put this ideal out of reach for the scale and budget of most Earthships.

This vision of providing all we need through maximizing the value of our space is awesome. We get it. We do. But it does not seem possible to produce enough food working at the scale of a single Earthship to meet this ideal.

According to the research completed by Kruis and Heun in 2007, a family of four living in an Earthship would require 98 gallons (370L) of water per day, or 37,500 gallons (135,000L) of water per year. They identified in their research that the water requirement was totally achievable in a wet place like Michigan, but those quantities could not be achieved in Hawaii, New Mexico, or Alaska. This corroborates our experience in Taos where most of the Earthship owners we know have to buy water. This makes a backup dependable water supply essential for many locations.

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CHAPTER I: The Myth of Build-Out Time and Reality Check: There is no such thing as a Global Model

While the legend is that an Earthship can be built in a few weeks, that does not seem to be most people’s experience. Most often, builder-led projects take from a few weeks to 2 months. When doing it on your own, an Earthship can easily take 2 years to build. 

The design and permitting process can also take years - first, learning for yourselves, then training the local code enforcement officials. With planning and permitting, a build can as long as 5 years. Are you ready for a multi-year camping adventure? Can you afford a hotel/rental for that time? Regardless of HOW you do it, you need a plan as well as cash flow to pull it off.

The Myth of “Will Perform as Expected in Any Part of the World, in Any Climate” or, Reality Check: There is no such thing as a Global Model

We love the idea of a convenient one-size-fits-all approach to design. However, the Global Model promise is one that fails to deliver, in Earthships, and an every other kind of architecture. The reality is: Not every building works in every climate. There is a thousand years of architectural and archaeological evidence in New Mexico that backs up this fact, and tens of thousands of years of evidence from around the world. Cultures migrated and modified their own home designs as they went. They did not do so because they were trying to be stylish or to merge with the new culture. They adapted to the new conditions because they needed to stay warm in winter and cool in summer. The only things they had to work with were natural forces like the sun and physics (gravity, thermal and liquid dynamics, etc.), the materials and tools they had available to them, and history. It was anything but convenient to have to adjust, but they did, because they needed to in order to survive. 

Let’s try an exercise. We are going to give you a new religion. We will not tell you what religion it is, but it is not from here, and we do not care what you were brought up as. We just want you to start being that religion, today. OK? Ready Set Go! What? You do not love that idea? Good, because we are not going to ask you to do anything of the sort because it is preposterous. It is, however, a decent metaphor to illustrate just how absurd the concept of a Global Model of design is for architecture. Many of the underlying reasons why a Global Model is infeasible are the same as why we cannot adopt a new religion from somewhere else around the world on a whim. 

First, there are cultural concerns. People around the world are building on traditions that have been developed over 10,000 years of their own settlement and technology patterns. They would be wise to be reticent to adopt a new building technology that is not proven, culturally appropriate, or technologically feasible. I think back on several projects I have worked on where sophisticated technology-based systems like water filtration systems, have been donated to worthy charities in third world countries. At first, wow! How they changed things for the better! New school uniforms were purchased from the proceeds from the sales of purified water, and a bustling business was born. But, then, a tiny plastic part broke. Suddenly, that awesome system turned into an expensive piece of wall art because the people who were gifted the technology did not have the knowledge, parts, access to alternatives, or technical know-how to repair it. 

Another great example to technological appropriateness in design came for me on a project I worked on in Peru. A non-profit organization wanted to build a 20,000 square foot multi-level concrete building and ceremonial space in a jungle that is only accessible by a 2 hour powered canoe ride. I kept asking, “How are you planning on building that?” knowing that cranes and a pump truck would be required. Someone would justify how it could happen using experimental technology that was not available in Peru. We could always have tried - spending huge amounts of money and effort to buy and ship the systems there and experiment with making it work. Finally I quit the project because I realized that my approach to design was too “traditional” and it would be an uphill battle to go simple within the context of these very big dreams. I stayed in touch, however, because I love the organization’s work. A year or so ago, I received a newsletter that announced they had finally built their facility in the jungle. When it came down to it, they built a 1,500 square foot building out of local materials and that was built by locals. However, it took them 2 years to break away from the big idea and back to something that truly worked for its place. The best news of all (for me) was that humble little building supported local crafts, culture, economies, and because of all that – it was both affordable and easily maintainable. That was good design. And it was sustainable.

Climate is another important criteria for why there can be no Global Model of architecture. There are different climates around the world and different microclimates within those climates. While ideas that work in Iran may a great place to start for ideas what might work in New Mexico, because they share similar climates, the wind directions, snowfall and rain amounts, soil types, and geography play important roles in differentiating how the designs perform. We can see this illustrated quite easily. In New Mexico, where many presume we are “all in the same climate”, there are actually 6 diverse bioregions that have different water, climate, agricultural, soil, and architectural properties. The architectural systems especially cannot be made to “fit” in all these regions. In the flat and hot desert, our traditional adobe homes with flat roofs placed directly on the ground are ideal. But in the mountainous regions, they utilize small easy-to-heat log buildings on sturdy foundations that elevate the homes out of the snow in winter. To ignore the sun or landscape is to risk overheating and/or water infiltration.

Few Earthships seem to place an emphasis on site selection for anything other than solar access and views. In one example of how this can go wrong, several Earthships were built at the Rural Earthship Alternative Community Habitat (REACH) near the Taos Ski Valley. The REACH community, despite the assertion otherwise in Garbage Warrior, is not entirely a success. Some of the Earthships at REACH are only used by the interns at Earthship Biotecture or as rentals during summer. Most often, the people staying there have no idea there are issues with these buildings because they are so happy to be part of the movement and living in the beautiful spaces with the stunning views in the summertime when the site is accessible. They most often do not recognize that those buildings are available to them for a reason – the spaces do not work for homebuyers. Homes in this prestigious area can sell for $300,000 or more – an expensive dorm room indeed! But the builders did not follow some basic but necessary design principles and thus, the buildings were difficult to sell. Not everyone wants to climb stairs in the dark to get into bed, to be colder than comfortable in winter, overheated in summer, or to go down a dark set of stairs into their closet. Or to listen to your neighbor’s conversations because the site acts like a natural amphitheater and the houses are placed too close together. Or have to abandon their essential veggie growing planters because their cat will not stop using them as a litterbox. Or to use the wench on their 4WD to drag themselves up an impassable snowboarding-worthy hill in the winter. REACH is an experimental dream that did not end up manifesting so well. Once it was removed from the Taos Plateau to a hillside just a few miles away from the original Greater World development, the weaknesses in the one-size-fits-all approach of the Earthship concept began to be revealed. Some of the issues were due to limited design understanding and poorly designed building details by novice builders, and some were due to the unique mountain climate and landscape that the design was not modified to respond to.

This is just one close example of how even small microclimatic variations can undermine the performance of a building. With every mile traveled away from Greater World, these issues become more challenging and more important to resolve. Once we get into the hot/humid regions, the idea implodes, and not just for Earthships. Buildings that work well in the high arid desert do not work well near the equator. Earthship Biotecture will go into areas hit by natural disasters to help them out by quickly building micro Earthships to try and assist in the rebuilding efforts. That is an awesome thing to do. The people in those areas need help now and they can assist, as well as attempt to work the Global aspect of their design out by modifying it for tropical climates. The only issue is that observers and users of these facilities report that the tropical models have issues, including lack of humidity control, lack of ventilation, poor lighting, wind channeling, mold, darkness, and worst of all… acting as a reservoir to capture hurricane water while shedding hurricane winds.

We need to utilize architectural tools here in New Mexico that you may not need where you are. In his article “Earthship Hype and Earthship Reality” on GreenBuildingAdvisor.com, building expert Martin Holladay points out that while a cistern may be required in New Mexico where we struggle to have enough water, a place like New England may not need the cistern because of the natural wetness of the climate and the predominance of springs and wells. Issues like this are why we need to pay attention to climate and not blindly follow the standard design when that standard does not work FOR us.

There are specific issues in the design of the Global Model Earthships. There are Code-compliance issues of not having a means of egress from every bedroom without passing through a secondary space. The new earth vents can render the berm dysfunctional and are, in some locations, wrought with snow, mold, and maintenance issues. The cisterns diminish the earth-sheltering benefits of the berm. Hidden hallways and an uninhabitable greenhouse account for an average of 50% of the space being unusable. Openings in the south wall in the living room render the greenhouse part of the space and thus create humidity and overheating issues which can rot furniture. This causes a demand for additional ventilation. The over-sizing of rooms and under-sizing of functional spaces, and the inclusion of the mechanical room and all of its noise and heat as part of the main body of the house are yet more design challenges faced by Earthship dwellers. We can do better.

The overwhelming evidence does not support a global model of design… and it is not a bias towards Earthships … neither Earthships nor any other building type works for everybody in every place. Evidently, Earthship Europe agrees, based on this quote from their website,

“…concerning the Global Model (one model for everywhere) I can only say:

‘Would you built an igloo in the desert?’”

Earthship Europe has modified the designs extensively to make them work for European climates, and their spinoff Flagship Europe has walked away from the Earthship concept entirely. That is one way that we can know if Earthships or any other new build type works in an area. We can ask how many more got built after the first one. And, if they changed things, what got changed? In many cases, Earthships are modified heavily so they perform adequately, often at great expense and over a long period of time. That fact is not advertised, or for that matter… even acknowledged. 

The most important factor we can suggest for those who really love this idea and want to make it work is to study everything you can about the vernacular architecture in the place you want to live. Visit every historic or archaeological site you can. Learn from these buildings and their relationship to their place, and adapt the design of your home to fit the area’s climate and existing building traditions. Then, think small. Design only what is needed for space, and then plan ahead for additions to make them easy. The Earthship firms will not guarantee that anything they design for you will be permitable, so you might as well tweak the design and make it work for you.

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CHAPTER I: The Myth of “The Most Efficient, Easy to Build Construction Method on the Planet”

Earthships require extraordinary amounts of time, patience, self-education, and physical labor to build. One builder noted that he could tell if people were “real prospects” to build an Earthship by testing them on a build site. He said, “I just let ‘em pound one tire full. It takes 3 wheelbarrows of dirt and a good pounding, and the first time they do one, it can take up to two hours that will rock their entire body. If they are standing at the end of it, they might be a candidate for building their own.” How many would-be builders are really prepared for this? Several of the people we interviewed ended up injured from all that pounding. There is a price for that, too.

While Earthships might be “easy to build”, there is no promise of producing a well-built result. This is an issue inherent in using unskilled labor, no matter what the building project type. People who have never built anything will not know what not to do. This can turn your home into a giant craft project. That might be okay for the hidden stuff, but what if you really care about your home being well-built and beautifully so? Several builders in our research noted that even with years of experience in constructing other types of buildings, the Earthship proved to be a monster project to both manage and learn the techniques for. 

The most concerning part of the “most efficient” issue is that the time needed for building the home is either devoted to, or sacrificed from, daily activities. If you are not independently wealthy and require a source of income, you have to sacrifice your time to build a home (which can be a full-time job in itself); in addition to having a job to make the money to pay for the home you are building. When this happens, the sustainability of the process comes into question.

Sometimes we need help – an expert – to get things built. But it is difficult to find an expert in Earthship building who can provide the help you need and that you can afford. We heard time and again… a lack of professional assistance can totally derail a project for unseasoned builders.

The Abandonment Phenomenon

Nearly a third of the people who contacted us after hearing about this project wanted us to share that they had given up on their Earthship dream, sometimes in mid-build. They felt like they had lost time, money, and even faith from their Earthship experience. Some had been injured. Some ran out of money. Others ran out of patience for trying to train building inspectors in something they barely understood themselves. Others could not figure out the systems, which, as one interviewee commented “required German language knowledge or an engineering degree to make work.” Still others gave up because other teams wanting to build Earthships in their area had failed to obtain permission. The most disheartening part was that the prospective builders who were forced to quit seemed depressed and demoralized by the experience. Once we knew to look for it, this sentiment was quietly echoed in the message boards and forums. Several sources in our research commented that people they knew had spent years pouring every penny and thousands of hours of sweat equity into their Earthship, and when the project was finally complete… they lived in them for a while and then sold their home at a loss just to “get out from under it.”

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