What I learned building my energy efficient dream home

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The average family home in the US generates more than 160,000 pounds of greenhouse gasses a year. Does building an energy efficient house pay off?

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RMI Outlet

I had long dreamed of building my own home. I wanted it to be beautiful, comfortable, healthy, and as environmentally friendly as possible. When my husband and I were finally fortunate enough to purchase a piece of land, I was ecstatic that my dream was going to come true. However, the hard work was just beginning. The average single family home in the United States generates more than 160,000 pounds of greenhouse gasses each year. How could we build our dream home and stay within our budget, all while contributing the least amount possible towards climate change? We learned that we had to make some tradeoffs, but that investing more up front was well worth it, as it ended up providing more comfort, reducing our carbon footprint, and saving us money in the long run.

Ignoring the Big Bad Wolf

The first decision we had to make was what to build with. I long knew I wanted to build with straw. While people who hear that always joke about the childhood fable of the big bad wolf, I was determined. Straw bales are highly insulating, environmentally friendly, and can be locally sourced. The R-value of straw bales is a bit controversial, but recent tests put a straw bale wall at R-30 to 35, perfect for the cold winters and hot summers of Colorado. Plus, straw is actually a waste product, what’s left over when grains are harvested. In the U.S. alone, over 200 millions tons of waste straw are generated each year, much of which is burned, contributing to air quality problems.

We designed the house ourselves, and although we might have been able to save money by building the house ourselves as well, we wanted to keep our full-time jobs and our marriage together (building a house together is one of the biggest stresses on a relationship), so we decided to hire a general contractor. One of our good friends happens to be a general contractor specializing in straw bale construction. Terralink Structures has built dozens of ecological homes in the area, many with straw, and I knew Keith, the general contractor, would let us get our hands dirty and be part of the building process, something many contractors dread.

One of the most rewarding things for me about building with straw is the ability to hold a community bale raising. Reminiscent of old fashioned barn raisings, where in the 18th and 19th centuries a community would get together and help a family build a barn so they could start their farm, a bale raising is a way to get the walls of your house up with the participation of friends and family. Although Keith told us it would probably end up being more work—and more cost—as he and his crew would have to fix the walls stacked by numerous untrained volunteers, he fully supported the idea as it’s a great community event. That was another conflict: do we go ahead with an educational and fun community-building event, or do we go the more economical way? We went ahead with the bale raising, and dozens of friends and neighbors came by and helped us get the majority of our bales stacked in one day. It was definitely worth it, as those memories are priceless.

But then the real conflicts began. We knew we wanted a low energy house, which meant eventually installing solar thermal and solar electric panels, to cover our heating and electricity needs. But what about the materials that go into a house? Many traditional construction materials have loads of embodied energy. We also wanted a healthy house, and many building materials have products containing a great deal of toxins. Keeping the embodied energy and toxin content of our house low meant using as many natural and “green” materials as we could, often meaning paying a premium.

Playing with Dirt

With a lot of south facing windows to capture the winter sun, we needed thermal mass to store that heat for the cold winter nights. Many people add thermal mass to their house in the form of concrete floors. Wanting to stay away from the high embodied energy of concrete, we got our thermal mass a few different ways.

For our floors we decided on poured adobe. Poured adobe floors are just what they sound like; a mixture of clay, sand, and a small amount of straw that gets poured into a floor, troweled, and covered with a natural finish like linseed oil. The end result is a beautiful, nontoxic, locally sourced, earthen floor. My friends from South America thought I was crazy wanting to live in a house with dirt floors. Plus, though the materials are inexpensive, the amount of labor to make a durable lasting adobe floor adds up, making it a pricey surface to live on. But while concrete and ceramic tile both provide great thermal mass, poured adobe seems softer and warmer to the touch, and has extremely low embodied energy.

I had also long been intrigued by the Cinva Ram, a manual press invented in Colombia that creates compressed earth blocks. What better way to make some interior walls than with earth excavated from our site. After two weeks and many sore muscles later, my friend and I had cranked out the estimated 1200 blocks I figured I would need for the walls I wanted to build. A day after pressing them they were ready to build with. We stacked them with an earthen mortar and covered them with linseed oil.

Low Energy Materials

Another big decision was the kitchen countertop material. Laminates require a lot of energy in the manufacturing process and often have adhesives with high VOC content. The extraction of granite and marble is both energy and water intensive, not to mention they are costly. We opted for Paperstone countertops, made out of 100% post-consumer recycled paper, VOC-free resins, and natural pigments.

Yet one more decision was what to cover our interior walls with. I love the look of stucco, but wanted to stay away from the embodied energy of concrete. We ended up covering our walls with earthen plasters, a mixture of clay, sand, and natural pigments. The result is breathable, healthy, soft, organic looking walls that make me never want to leave my house.

Trying to build as “green” as we wanted to, while also fitting into our budget, proved to be tricky, and we had to make some compromises, but we were happy with the finished result. And though we spent more money on certain items than we planned on, we realized that the energy savings on our heating and electric bills more than make up for it for the extra money spent up front. And if we add in the health and emotional benefits of living in a natural comfortable house, along with the amount of greenhouse gas emissions reduced through some of our building choices, we come out even further ahead. But most importantly, we have a beautiful passive solar earth-friendly PV-powered house that we can call home. Of course, you don’t have to build with straw and dirt to make an energy and resource efficient house. But you do have to realize that investing in quality and high performance materials from the beginning pays off. And to those naysayers who don’t believe in building with straw, I tell them the moral of the story is not to let a pig build your house.

This article was originally published on the Rocky Mountain Institute’s Outlet blog. Reproduced with permission

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1 Comment
  1. John P 6 years ago

    This is a typical American story, but it is redolent of the OZ experience too. The worry about embodied energy is understandable but is not all that significant. Any object we decide to use will represent some level of embodied energy. It is beyond our control to deal with that. The manufacturer has to deal with that.

    The key is to reduce and replace the energy involved in our development.
    These days it is easy enough.
    I live in a zero emissions house so for me the troglodytes in the new government may well dismantle the existing environmental standards but at least I have done what I can.
    And I have saved a small fortune in the process.

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