Friday, October 19, 2007

CMI: Efficient Buildings

Article 7 in a series that looks at Princeton's Carbon Mitigation Initiative, which has outlined 15 carbon reduction strategies, in 4 broad categories, each of which could be scaled up to provide 1/7th the CO2 reduction necessary to stabilize the atmosphere.

Carbon Mitigation Initiative:
Category 1: Efficiency and Conservation

Efficient Buildings:
Programs promoting or mandating efficient buildings in the U.S. are still in their infancy. Two voluntary programs deserve special mention.

A section of Energy Star is devoted to promoting efficiency in new and retrofitted homes. Their program focuses on reducing the energy needed for heating and cooling:

Sealed Ducts and Leaks
Efficient Windows
Efficient HVAC, Lighting and Appliances

About 200,000 new Energy Star qualified homes were built last year, about 12% of the total, and another 12,000 were overhauled to improve efficiency, bringing the total to 725,000 and 26,000 respectively. Energy Star homes are between 15 and 20% more efficient than those built to "code." Energy Star is currently partnering with about 3,500 builders.

The organization that has been getting the most media attention is LEED, or Leadership in Energy and Environmental Design. Created by the U.S. Green Building Council, LEED is system that rates buildings for sustainability. According to their web site:

"Based on well-founded scientific standards, LEED emphasizes state of the art strategies for sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality. LEED promotes expertise in green building through a comprehensive system offering project certification, professional accreditation, training and practical resources."

While I have had difficulty finding numbers that give an estimate of the impact of LEED, their roster lists something in the neighborhood of 6000 registered projects, representing many million square feet. Given that the certification process only began in the late 1990s, and that in 2002 there were only 12 registered projects, growth in this area has been remarkable. More significantly, thousands of architects and building professionals have become LEED "certified," holding out the promise that these key professionals will make sustainable building the norm.

Certainly, LEED is associated with cutting-edge design, which will hopefully increase its influence, especially with young professionals. One risk, however, which is evident throughout the Green products arena, is that instead of becoming the norm for new buildings, LEED will become more influential as a prestige label. In New York City, certainly, it is best known for a hand-full of ultra-luxury, high-profile "starchitect" projects rather than for more mundane commercial and residential building.

While these voluntary programs have shown impressive growth, again mandatory standards are clearly needed to make sure our building stock is as efficient as possible.

Judging from a paper published on their web site, the National Association of Home Builders is as opposed to mandatory standards as the electricity or auto industries. They draw the following conclusions about emissions tied to residential housing:

• More than half of the energy consumption and CO2 emissions attributable to the residential sector is the result of energy “lost” in the generation and transmission of electricity.

• New homes (those built in the last ten years) account for about 12 percent of residential energy consumption.

• Per square foot, new homes consume less than two-thirds the energy of older homes for the core HVAC uses controllable by builders.

• Behavior of the occupants has a larger impact on non-HVAC energy consumption than those items under the control of the builder.

• More stringent energy conservation requirements for new homes can have a reverse effect of retarding filtering and keeping people in older, less energy-efficient homes.

In other words: the new houses we build are not the problem, old houses are; it's the owners not us; it's the electric companies not us; if you mandate efficient building, people will decide not to move or renovate.

Given the difficulty of educating and motivating 3oo million people, Green Factoids would argue that the least effective and efficient way to control home energy use is by focusing on individual decisions. Is it even helpful for the average person to become knowledgeable about duct-work and high-efficiency windows? It seems clear that if we are going to achieve anything close to one wedge of reductions from efficient buildings, builders should be pressured and ultimately required to maximize efficiency in those areas directly under their control, whether or not homeowners know enough to ask for these measures or not.

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