Renewable energy and EVs are just a few pieces of the puzzle for achieving net-zero living. But what if we could combine eco-friendly building materials, energy efficiency, and sustainability, like a passive house, but being heated and cooled by the ground without relying on the electrical grid? It’s time to get on board an Earthship … it’s a house … not an actual ship. What are they, where can they be built, and are they worth it?
There’s a lot of focus on getting solar panels for your home or buying an EV to help go net zero and save money in the long run, but that’s only one piece of a much larger puzzle. Finding ways to reduce our energy use and live more sustainably is just as important, like building a net-zero or passive home. Or using smart technologies to optimize how and when things inside your home use energy. I’ve done several videos on various aspects of those concepts already, but just like the passive house standard, there’s another building technique that doesn’t get as much attention. While I don’t personally see myself building or living in an earthship house, which sounds like something that’s meant to travel the galaxy, I found myself endlessly fascinated by the approach … and how some of the principles can apply back to more traditional, mainstream approaches.
In the construction sector sustainable buildings like passive homes and green buildings are gaining traction and are important solutions for a low-carbon future combined with renewables, EVs, and battery storage.
These home designs naturally reduce carbon emissions from heating and cooling, which is a very good thing when you consider that heating and cooling accounts for 51% of the total energy use in the U.S..1 Even though green buildings and passive house designs have a positive impact, they still rely on the electrical grid and public utilities, which depending on where you live, isn’t as reliable as it should be. But what about an approach that could pull together energy efficiency, upcycled materials, even food production and cooling from the earth itself, combined with off-grid living? And do it for less money than building something like a passive house. Enter Earthships.
Built with eco home building materials, Earthships offer comfortable, energy efficient, and cosy living spaces without relying on public utilities. I’ve been drawn to solar power and battery storage in my grid-tied system to try and reduce my dependence on the grid, but not cut it altogether. This, on the other hand, takes things to a whole other level.
It all started in the 1970s in New Mexico with the architect Michael Reynolds. He proposed the inclusion of bioecological features like beer cans, old tires, and bottles into his designs, which was … very curious at that time … well, even today.2 3
Earthships can be boiled down to six basic design principles.
1) Building with Natural and Repurposed Materials:
Some of these materials are available in abundance worldwide. In the U.S., for example, about 290 million tires were scrapped in 2003. Just one year. Most of that is chopped up, burned, recycled into other products, or buried in landfills. But there are millions of tires stockpiled every year, so you can get them very cheap or sometimes for free.4 5 When they’re used in earthship construction, old tires are used as “bricks.” They’re filled with earth that’s pounded to create very strong exterior walls and load-bearing interior walls. They have a much higher thermal mass than traditional construction. A study by the Colorado School of Mines showed an R-value of 40 for a tire bale wall. That’s three times as much insulation as a standard 4″ stud wall.6 Other materials such as cans and bottles are optional, but they can also be used as the main material to construct interior walls, which are then plastered. 3 7
2) Thermal Solar Heating and Cooling:
Earthships naturally heat and cool themselves, so don’t require electric heat, fossil fuels, or wood … depending on where you live, which I’ll get to in a bit. The tires, which I already mentioned are known as bricks, can weigh 300 pounds when packed with soil. That incredible thermal mass isn’t just a good insulator, but it can store heat or cold.
The basic idea behind heating and cooling an Earthship is to surround each living space with those thermal mass bricks on the east, north, and west sides. On the southern facing side you line that wall with windows. The sun shines through the glass, warming the mass of the floors and walls. When the sun goes down and the air temperature drops below the temperature of the walls, heat flows from the walls and the floor into the living space. It’s the the same passive solar principle that’s used in some passive home design.3 7 For cooling, there are cooling tubes fed through the thermal mass surrounding the building. As warmer air is pulled into the building through those tubes, the heat is wicked away providing cooled air to the inside of the building.
3) Solar and Wind Energy:
Earthships produce their own renewable energy through solar panels and wind turbines. This part I’m sure you’re familiar with, but they’re able to provide power to appliances from solar and wind generation combined with charge controllers, inverters, and batteries to store excess energy for consistent power 24 hours a day.
But solar panel and wind generation systems like this can be expensive, so to make it more affordable with a smaller energy generator build out, you typically pair this with super energy efficient appliances, like pumps, lighting, and refrigerators. Together with natural cooling and heating to reduce the power demand, Earthships only require about 25% of the electricity consumed by a traditional home.3 7
4) Water Harvesting:
Now this one I’m interested in for myself. To further improve sustainability, Earthships collect and store rain water and snowmelt in cisterns to supply all their demand. There’s a great YouTube channel, Handeeman, who lives in Arizona and has done this exact thing. A few weeks of rain during the rainy season in Arizona and he’s got water for the rest of the year.
Water from the cistern has to be pumped through a filtering system to treat the water. But you can also use a solar water heater for hot water and use a pressure tank to regulate the water pressure.7
5) Contained Sewage Treatment:
Who doesn’t like talking about sewage? Trust me … this isn’t going to be gross. It’s all about reusing water to not let anything go to waste. And no, I’m not talking about having to take a bath in toilet water … but the water that’s left over after washing the dishes, doing the laundry, or taking a bath. This type of water is known as grey water. It’s basically used water that doesn’t have any fecal contamination in it. You can use grey water to feed interior botanical cells where plants naturally treat the water until it’s clean enough to be pumped and used for toilet flushing. When you’re talking about 40% of typical water use in a house getting flushed down the toilet, this can be a significant savings in water usage. Grey water reuse is standard practice aboard the space station … and for the nerds out there … it’s like the stillsuit in Dune.
For water that gets flushed down the toilet in an Earthship, it flows to a standard septic tank and leach-field, but you can also add a line out that overflows into an exterior rubber-lined botanical cell, taking advantage of the … um, rich nutrients shall we say … contained in the isolated cell for exterior decoration plants.7 8 Which leads me to the last principle.
6) Food Production:
One of the more recent experiments by Michael Reynolds’ company, Earthship Biotecture, is the use of interior gray-water botanical cells for food production. Taking all of that waste water to grow things inside the building. In Taos, New Mexico, the Earthship Visitor Center features herbs, peppers, tomatoes, kale, beets, and cucumbers for staff members to enjoy. Again, this is all tapping back into the concept of reusing and maximizing efficiency of every system in the home.
There are several pros that make the Earthship concept attractive. They’re highly efficient buildings that don’t rely on the power grid. Water is collected, filtered, stored, and reused many times … and for several uses. In addition, Earthships are made of natural recycled materials, require no HVAC systems (sort of), and provide organic food that’s healthy for people.
But is it all sunshine and rainbows? Let’s start with a great question that usually comes up around Earthships, and one that I’ve hinted at a couple of times: can they be built anywhere?
Well, cooler and more humid environments, like the American Northeast and Canada, can make it extremely challenging. In general an Earthship operates the best in a temperate or hot environment with regular rainfall over 50 inches per year and humidity less than 60%. Orientation is also vital, which might make certain locations impossible. A rule of the thumb is to face windows to the southwest if you need more heat and southeast if more cooling is needed. And water tanks should be placed on the northwest if you build an Earthship in a cold climate to prevent them from freezing. And on the northeast in a hot climate to prevent overheating. 9
Earthships in a very cold climate have divergent opinions. Although Reynolds has modified some of his Earthship plans to make them better suited for the cold, his buildings don’t have heat pumps to extract heat from the ground. In Canada, for example, the ground temperature is below 7º in the winter, so keeping the inside living warm gets harder. 10 Again, it’s not impossible, but takes modifications to keep it warm. There are a few Earthships I found in the New England area that had to integrat some form of traditional heating system for certain times of the year.11
Another problem of Earthships self-sustainability is that homeowners can’t grow all the essential food they want because some food is impossible to grow inside the Earthship. Even more important, some residents might not have the necessary farming experience.
And regarding water collection, it’s hard to have enough rainwater volume in some arid climates. I mentioned that YouTuber from Arizona, well, he’s able to do it with a fairly sizable rain harvesting system, but that may not be the case everywhere. Earthships also accumulate water in the wall surfaces which might lead to the formation of molds and algae, and the tires used in the walls can break down and expel gases into an enclosed space, which can be harmful to the inhabitants. 12 13
And then there’s the costs, but there are a lot of factors that affect how much it will cost to build.
While a conventional house costs $100 to $150 per square foot on average … not accounting for the cost of the land … Earthships cost between $150 and $225 per square foot, which is considerably more expensive. But their cost is not that different from passive homes, which ranges from $166 to $231 per square foot, which I covered in my Passive House video. 14 15
The price of labor is usually one of the highest expenses when building an Earthship since they require unique building methods. If you’re going to do the labor yourself, it will obviously cost a lot less than the $150 to $225 per square foot But imagine placing all those tires, compacting them with dirt to make the walls. Placing only one tire takes from 45 minutes to one hour, and you need hundreds of them. Doing this yourself is definitely an option, just not for the masses.
Also, due to their unusual design, an architect or engineer with the experience and knowledge to carry out the project may be more expensive. There can also be issues with modern building codes and permits that can come up.
Excavation to grade and level the site, and provide a solid foundation also brings considerable costs, not to mention all the soil that’s needed for the walls. 15
But there are plenty of examples of Earthships out in the world. In Taos, where Earthships were born, sits the 600-plus-acre Earthship community, which has space for 130 homes.16
Far from Taos, we have the Brighton Earthship, in the U.K. Built in 2007 by Earthship Biotecture and the Low Carbon Trust, it serves as a community center for the nonprofit Stanmer Organics. 17
In Alberta, Canada, the 1,800-square-foot Kinney Earthship was built with more than 12,000 cans and 800 tires. Mike Reynolds carried out this project for a whole summer. He brought a dozen workers and thirty volunteers from New Mexico to help complete it. The Kinney Earthship produces all its own electricity, grows much of the family’s food, and recycles all greywater. 17
And there are more Earthships in other parts of the world like in Scotland, Nicaragua, South Africa, and more.
I hope it didn’t sound like I was bagging on the concept of Earthships when going over the cons, but there are significant challenges to where you might want to build one. With other building techniques that can provide as energy efficient a home, at the same cost, with less restrictions, it kind of relegates Earthships to the highly motivated … more a niche option. Despite all of that, Earthships are a fascinating concept that has aspects that could be applied elsewhere. Things that not only benefit the environment, but also give you more independence and potentially save money over time with much lower energy requirements. It’s another piece of the much larger puzzle.
- EIA – Use of energy explained, Energy use in homes ↩︎
- These Otherworldly “Earthships” Offer Visitors Unusual, Off-the-Grid Accommodations ↩︎
- Sustainable Homes: The Earthship ↩︎
- EPA – Scrap Tires ↩︎
- Wikipedia – Tire recycling in the United States ↩︎
- Building with Tires for Energy Efficiency and Disaster Resistance ↩︎
- EARTHSHIP DESIGN PRINCIPLES ↩︎
- What is Earthship? ↩︎
- TIPS AND TRICKS TO MAKE Earthships WORK ↩︎
- DO Earthships WORK IN COLD CLIMATES? ↩︎
- VTDigger – A house made of trash and tires in the NEK makes an eco-friendly ‘earthship’ ↩︎
- Earthship Designs, Importance, pros and cons + DIY kit. ↩︎
- Thinking About an Earthship? (Pros and Cons) ↩︎
- How much does it cost to build a house ↩︎
- How Much Do Earthships Actually Cost to Build? ↩︎
- Way Off The Grid: 6 Earthships That You Should Know ↩︎
- Way Off The Grid: 6 Earthships That You Should Know ↩︎