A sustainable design pyramid
How not to lose sight of the big picture.
Mon, Mar 21, 2011 at 04:58 PM
Designing a house is a complicated task. Anyone who has ever built a home knows that there are literally thousands of design decisions to be made, ranging from the smallest detail (what color of grout do I want in my shower?) to the largest of issues (how big should my house be?). In between there are a wide array of technical decisions, stylistic questions, and functional issues to resolve. The addition of a sustainable design agenda to “green” the house complicates the whole process even more.
Every choice you make about a house is a design decision and every house is the sum of all of these many choices. A truly sustainable home is one in which all design decisions, from large to small, are made with an eye to reducing the house’s environmental footprint without jeopardizing its livability. To better understand what this means in practical terms, the Slow Home philosophy organizes the various aspects of residential design into a four level design pyramid. The goal is to help you make more balanced and effective sustainable design choices when either building a new home, remodeling an existing residence, or perhaps just buying a resale house.
The top of the pyramid: Aesthetic choices
At the top of the pyramid are choices about finishes, materials, colors, fabrics and furniture. These interior design decisions are significant because they define the quality of the surfaces that we see and touch on a daily basis. Green design in this context is about making choices that focus on such things as rapidly renewable finishes, recycled content materials, low volatility paints, and natural, low toxicity fabrics. On their own, however, decisions at this level are not sufficient to make a house sustainable.
The second level: Exterior design
The second level of the pyramid deals with exterior design issues such as building style, roof shape and window placement. These decisions are important because they define not only how the building looks from the street but also how effectively the construction performs. From a green design point of view, this level of design primarily involves ensuring that the massing of the building is compact, construction materials are efficiently used, and the building envelope is designed for optimal thermal efficiency. This means paying attention to the design of the roof and wall insulation systems as well as properly detailing the windows and doors to minimize air and heat transfer. Like interior design, however, this kind of decision making does not, by itself, constitute green design.
The third level: Systemic choices
The third level of the pyramid is about technical design decisions regarding the electrical, mechanical and plumbing systems. Green design in this context is about making choices that reduce water and energy usage and employ renewable technologies and clean energy sources. These design decisions use technological fixes to optimize energy usage and reduce the amount of greenhouses gases that will be generated by the operation of the house over its lifetime. Technical design plays a very critical role in making a house sustainable, but as with the other levels, it is not sufficient on its own.
The foundation of the pyramid: Location, size, orientation and stewardship
At the bottom of the pyramid is the most fundamental level of design decisions. These involve a consideration of the basic elements of inhabitation that are not normally considered in discussions about green design. In actuality, however, they are the foundation on which all other sustainable design choices should rest. This level of design focuses on issues of location, size, orientation and stewardship. From a green design point of view, it’s about ensuring that the broad decisions you make about where and how you live are properly aligned so as to reduce your overall environmental footprint.
Why the design pyramid matters
Good sustainable residential design involves a coordinated approach that simultaneously engages all levels of the design pyramid. If green design thinking is limited to only one or two of the levels, the result will not be a truly sustainable home.
For example, at present, too many people limit their green choices to interior design issues. It’s all about bamboo floors, low-VOC paint, and recycled countertops. While these are certainly significant choices, in the absence of a more comprehensive approach to sustainability, their impact will be severely limited. It’s like worrying about the toxicity of the dyes in the cushions on the deck chairs of the Titanic. Important, but it won’t prevent the boat from sinking.
In much the same way, an engineering approach that concentrates too heavily on the technical level of design is also an overly limited way of thinking about sustainability. It’s all too easy to get caught up in the technological paraphernalia of sustainability and end up missing the forest for the trees. Heat recovery ventilators, low flow toilets, geothermal heat pumps, and solar arrays are important but their effectiveness is greatly diminished when they are not part of a more comprehensive sustainability strategy that extends to all four aspects of the design pyramid.
Practical sustainability is about making every design decision a green issue. Substantially lowering our environmental impact will not be achieved by just purchasing a few green products or attending to a narrow set of issues. In the end, these kinds of choices only serve to make us, and the homebuilding industry, feel better.