How to design your green dream home
by Kelly Hart
Are you dreaming about that cozy, energy efficient, green home that suits your needs perfectly? Perhaps the best way to realize this dream is to design and build your home from scratch, so that it fits your preferences for location, aesthetics, principles, and budget. This article will guide you through some of your basic choices to help you design an ecologically sensitive abode.
The very first consideration in good home design (as opposed to house design) is where to build. The location is paramount, not only because it must fit your needs for proximity to work, schools, and shopping, but also because it must provide space for privacy, gardens, solar access, and all those intangible qualities that create a sense of place.
Choosing the exact site for your dream home is a Zen art, so don’t hurry the process. Spend some time on the property where you might build, and get to know it. Observe what views inspire you. Feel where the wind blows and notice where the sun shines. Pay attention to where the water flows during a rainstorm or where snow tends to pile up. Your home needs to be sited where the water drainage flows away from the footprint of the house.
Next you can begin playing with floor plans and elevations. You can decide if you want the whole house on one level, or whether second or third stories are appropriate. One of the primary tenants of sustainable architecture is to keep it small, no larger than is really necessary. Compact designs have many advantages: they use less material to build; they are more efficient to heat; they are more convenient for living; and they feel more cozy and embracing than larger houses.
If you make a list of all of the functions that you want your house to perform, you can go through it while looking at your design ideas to see if you have provided space to accommodate every need. For instance, if you like to dance, be sure to list this so there will be an area where there is room to move.
The idea of digging into a hillside to keep the home snug can be expanded to totally earth-sheltered concepts, where most of the home is buried, including the roof. There are many advantages of doing this, as any ground squirrel would tell you: deep in the ground the temperature stays about the same all year round. The buffering effect of the soil can make a huge difference in heating and cooling costs year round. Another advantage of complete earth sheltering is that the footprint of the house can be given back to nature, by allowing the roof to literally become a garden.
Designs that utilize passive solar concepts for space heating make so much sense that I feel this strategy should be employed in any dream green home. All you need to do is make sure that the longer axis of the design faces more or less south, and then place some glass in that direction. In our climate, the area of this south-facing glass should be between 20% and 40% of the floor area of the room that it faces. Windows that face the other three directions should be fewer and smaller so that the stored heat is not lost through them.
To collect all of that heat from the sun, and to keep you warm when it is not shining, you can incorporate lots of thermal mass into your design. Heavy masonry materials can be used to construct some parts of your home’s interior, especially those parts that will be bathed in sunlight, such as the floor near the windows. To enhance the ability of this mass to do its job, choose dark colors that absorb more heat, and plan to keep that area relatively free of furniture or rugs. During the summer, this same mass will help keep your home cool, moderating the fluctuating temperatures.
To avoid unwanted sunlight during the summer months when the sun angle is high, you should design architectural features that do this automatically for you. The most common way is to have substantial eaves (perhaps two feet) that overhang the southern window area.
If you like year-round fresh garden produce or ornamental plants, then you might want to design an attached solar greenhouse as part of your dream home. Most of what was described above about passive solar heating designs is true about attached greenhouses, except that there needs to be more glazing, especially from above.
Bringing so much sunlight into a greenhouse can overheat the space in the summer, so it is essential to design some way to vent this excess heat back outside. During the cooler months the extra heat can be utilized in the rest of the house through door or window openings or with ducts and fans.
While thinking about solar energy, you might want to consider your options for heating your domestic water and for providing at least part of your electrical needs. Both solar water heating panels and photovoltaic panels for electricity require year-round solar exposure. The place for these can be part of the house design, usually on the slope of a south-facing roof.
One final function of your dream home that most people don’t think about (but should) is a naturally cooled pantry. Rosana and I find our pantry indispensable. It is conveniently located right next to the kitchen, on the north side, where it is dug into the hillside and then covered with more earth. This underground space is always cooler than the rest of the house, but it never freezes.
Now that you have considered all of the various functions that your dream home should provide, and have come up with a basic, rough sketch of what it will look like, it is time to consider what materials you want to use to build it. Most people think that this is the first thing to consider when dreaming of a green home, but it should actually be nearly the last! This is because until you have planned just what the house will look like, and how it will be situated on your land, you cannot make wise choices about materials.
For ecological reasons, I suggest that you plan to use as little wood as possible in your dream home. The wood that you do need to use should be certified as harvested sustainably (such as FSC), or use recycled wood. One exception to this rule is the use of cordwood to build with, since this technique employs short pieces of small dimension wood (like firewood) which is easily harvested in a sustainable manner.
When considering materials to build with, there are two other rules: choose natural materials that have undergone little industrial processing, and find the most local sources for these materials as possible. If the material used is renewable (such as straw bales), so much the better. Also, natural materials tend to be non-toxic and impart a sense of earthy grace to your home.
There are two broad categories of building materials: those that insulate and those that store heat (thermal mass materials). Natural insulators tend to be light in weight and include straw bales, cordwood, pumice, cotton, wool, cellulose, papercrete, and lightweight concrete. Natural thermal mass materials tend to be heavy and include rocks, adobe, rammed earth, cob, bricks, and tile. Here in Crestone we have extremes of temperatures to deal with. For this reason the best way to keep your home comfortable is to make the outer shell from insulating materials, and then use the thermal mass materials on the inside to help maintain an even temperature. Walls can be composed of combinations of these materials, but the same order should be maintained.
I would suggest allowing your walls to breathe some, without putting a moisture barrier on them unless absolutely necessary. This will help keep a healthier interior environment and also allow moisture sensitive materials (such as straw) to dry out if they get damp for some reason. Obviously, any materials that will be buried in the ground must be capable of withstanding the pressure and possible dampness of that environment, and should not be breathable.
It can often pay off to remain somewhat flexible about some aspects of your design in order to be able to take advantage of recycled or inexpensive materials when they become available. For instance, you can frequently find phenomenal deals on windows if you are not tied to specific dimensions, because glass shops usually have an inventory of glass that was ordered in the wrong size or never picked up.
Getting your dream home design down on paper may be challenging, but I suggest that you persevere to the best of your ability, even if your sketches are rather rough. The more detailed your drawing, the better you will know just what you want, and this will help others visualize your dream also. You may need to hire a professional draftsperson or architect to complete your plans for review by your local authorities, or for whoever will be doing the actual building. Even if you plan to build your own home, I suggest that you make an effort to draw cross sections and construction details to help you picture exactly how it will be built. It is much easier to correct potential problems on paper than after they are staring you solidly in your face!
To learn more about every aspect of sustainable architecture discussed here, you might browse my website, www.greenhomebuilding.com. I encourage you to dream about your ideal green home in a joyous way, take positive steps toward realizing it, and before you know you will be actually living and dancing in your very own personally designed home. Little in life can be more satisfying!