Energy Use Is the Most Important Aspect of Green Building
Compared to energy use, material selection hardly matters
Articles on green construction, including those published on the Green Building Advisor website, contain information on a wide range of topics, including material choices, indoor air quality, landscaping, and the VOCVolatile organic compound. An organic compound that evaporates readily into the atmosphere; as defined by the U.S. Environmental Protection Agency, VOCs are organic compounds that volatize and then become involved in photochemical smog production. content of paint. This wide array of information can convey a false impression — namely, that the covered topics are equally important.
If you’re building a new house, most of these topics turn out to be irrelevant. From an environmental perspective, the most important factor by far is energy use — not energy efficiency, but actual energy consumption. Consider the following information:
● "The ongoing energy use of a building is probably the single greatest environmental impact of a building, so designing buildings for low energy use should be our number one priority.” — “Establishing Priorities with Green Building, Environmental Building News, September 1, 1995.
● "Although important, initial embodied energyEnergy that goes into making a product; includes energy required for growth, extraction, and transportation of the raw material as well as manufacture, packaging, and transportation of the finished product. Embodied energy is often used to measure ecological cost. is nearly always dwarfed by the energy consumed by a building over its lifetime. … Over the first 50 years, the initial embodied energy is less than 1/12th of the operating energy." —"Embodied Energy: As Important As Low Energy Design?" by Stephen Thwaites.
● "As far as I can tell, focusing on construction materials in isolation — and to the exclusion of other impacts of owning and operating a home — is a mistake. … I combed through CORRIM’s [Consortium for Research on Renewable Industrial Materials] life-cycle analyses to try to find the total difference, over 75 years, between carbon emissions for a steel-framed vs. a wood-framed home. And when you add together all life-cycle carbon emissions — for manufacturing and transporting the materials, building the home, maintaining, heating, cooling and lighting it for 75 years, and dismantling and disposing of it at the end — the difference between the two isn't much more than a rounding error. … When I look into CORRIM’s numbers, it's pretty clear that the big carbon impacts from a home are from heating, cooling, and electric power consumption, which typically have little to do with the choice of framing materials. Far more important than framing are the energy-efficiency features of a house. Excellent insulation, passive heatingSpace heating that does not require electricity or fuel consumption. The most common type of passive heating system is passive solar heating — that is, heating which depends on solar gain through windows, thermal mass, and insulation. Unlike an active solar heating system, a passive system has no pumps or blowers. and cooling, good daylightingUse of sunlight for daytime lighting needs. Daylighting strategies include solar orientation of windows as well as the use of skylights, clerestory windows, solar tubes, reflective surfaces, and interior glazing to allow light to move through a structure., and so on can make a huge difference to long-term climate impacts — far more than the choice of a wood versus steel frame. And perhaps more important than any of these is the size of a house." — "Framing: The Debate" by Clark Williams-Derry.
According to climate scientists, the burning of fossil fuels is bringing our planet close to a dangerous tipping point. To equal the global average per-capita use of energy, Americans would need to reduce our energy use by 83%. But even such a drastic reduction in energy use would not achieve a sustainable result, since the world’s level of energy use is clearly unsustainable.
"Sustainable" land development?
The word “sustainable” is bandied about far too casually these days. It’s easy to understand the meaning of sustainable forestry. But anyone thinking about building a new house should ask, “What is sustainable land development?” Clearly, the sustainable level of global land development is zero acres per year — or perhaps even a negative number.
So here’s my advice to anyone thinking of building a new green home:
- The best approach is not to build. Since the number of people per household in the U.S. has been dropping for years, a strong argument can be made to support the proposition that the U.S. already has too many houses.
- It’s better to renovate an existing building than to build new.
- It’s better to live in a small house or apartment than a large one.
- To lower energy use, strive to improve the airtightness and insulation levels in the building where you now live.
Of course, a perfectly reasonable argument can be made in favor of building a new house. But please don’t call it sustainable.
- City of Greensboro, NC
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