Beyond Energy Efficiency: Every Building Is a Long-Term Contract with the Environment. Here's the Fine Print
Magwood, Chris, Alternatives Journal
PRETEND that you are about to build a modest home somewhere in Canada. You've made the appropriate arrangements with designers, building officials, contractors and suppliers. The only thing left to do before you start construction is order the 75,000-litre railway tanker full of gasoline that you'll burn to provide the energy required to build the house.
Okay, you won't actually need that 75,000-litre tanker on your construction site. But, shockingly, your construction project will consume the equivalent of its contents before you move into your new home. The harvesting, processing, transportation and insulation of all the building materials require energy inputs, and the term used to describe these inputs is "embodied energy." The Canada Mortgage and I lousing Corporation estimates that for a standard house in Toronto with a 40-vear life, the total embodied energy is 2352 gigajoules. Therein lies your tanker with enough gasoline to drive a car around the equator 20 times, or provide 16 years' worth of household electricity.
When we build our homes, we are entering into what author Dan Chiras calls "a long-term contract with the environment." That contract begins with the vast consumption of resources used to construct the building, and includes a continued commitment to consumption as demanded by the performance of the home and the behaviour of the occupants throughout the building's lifespan. It also includes the end of its life;, when the embedded resources are disposed of or reused.
It is only when we reach an understanding of the four-clause contract described below that we will begin to reduce the size of that 75, CK)0-litrc tanker and move toward sustainable building.
Clause 1: Energy efficiency
Most Canadians understand that the amount of energy they consume at home has a direct effect on the environment. They also recognize the impact of rising energy costs on their personal budgets. As a result, energy efficiency is a growing priority for homeowners and builders. Over Haifa million Canadian households have participated in ecoENERGY, the federal governments energy efficiency home-upgrade program, and an increasing number of homeowners are seeking ratings from performance systems such as LEED, Passive 1 louse and EnergyStar. The number of Ontario homes enrolled in EnergyStar, for example, more than doubled to 10,000 between 2006 and 2007.
It's hard not to see this as a good thing and ifs certainly not bad, but energy efficiency tends to eclipse the rest of the contract with the environment as we blindly pursue this one clause, in the name of energy efficiency, a homeowner might embody so much energy in his or her house by adding more insulation and extra windowpanes that it negates years of energy savings.
The pursuit of energy efficiency in homes, while highly desirable, is also the wildest variable in our contract with the environment because it is so dependent on occupant behaviour. Occupants m a very efficient house could easily consume more energy than a conscientious occupant in an inefficient house if they leave the plasma television turned on, crack open windows during the winter and ignore basic maintenance such as weather stripping.
Energy efficiency is important, but we need to recognize that it is only one off our considerations that lead to sustainable building.
Clause 2: Embodied energy
The railway tanker of gasoline is a vivid illustration of the energy embodied in our building materials. Yet this part of our contract is often completely overlooked even though, unlike energy efficiency designers and builders can control the amount of energy that is embodied in a building. Whereas energy efficiency comes down to occupant behaviour, a building designed to have the lowest possible embodied energy will definitely have less of an environmental impact than its high-embodied-energy counterpart. …