Green and Super-Sized?

October 8, 2007

Can a 10,000 square foot house really be green? Is a hybrid GMC Yukon SUV an oxymoron? At what point does the alleged greenness of something go from truly being green to mere greenwashing?

The environmental bandwagon is getting crowded as more and more people recognize the benefits and importance of going green. Sometimes it is out of a genuine sense of commitment to green principles. But sometimes it is just marketing.

Green houses are one area where this is becoming an issue. Houses which many people would consider oversized behemoths are being touted for their supposed greenness. In a recent article, Jetson Green pointed out the absurdity of a 9,800 square foot house in Larkspur, Colorado being called a "green" building. A couple of weeks ago, when I attended a GM-sponsored event (along with David Anderson), I test-drove a 2008 GMC Yukon Hybrid. How truly green are these?

A new LEED for Homes standard is coming out later this year. One contentious issue is that LEED-H factors in the size of the house in program in a way that will penalize larger houses and require them to earn additional points in order to obtain LEED certification due to their larger size.

The USGBC has taken a very important step by setting the LEED-H standards so that builders cannot easily "greenwash" bigfoot houses. An example 15,000 square foot house in Florida that Lloyd Alter discussed had to earn an additional 26 points to achieve the same certification as an average-size house with a typical square-foot-to-bedroom ratio.

In many ways, LEED is about having a badge of status, rather than about building a green building. There were environmentally-sensitive buildings built before LEED was even introduced. There are buildings that incorporate green features that are not LEED certified. LEED is as much a marketing tool as it is a method for building green buildings. But if the builders and the owners want to ausuage their guilt about having an excessively large house, while they certainly can (and should) still build it as green as possible, LEED will not provide an easy shield to hide behind.

LEED-H offsets the requirement thresholds for its certification levels by raising the number of points needed for a larger home and reducing the number of points needed for a smaller home. The baseline figures are:

  • 2 bedroom house 1430 square feet
  • 3 bedroom house 1950 square feet
  • 4 bedroom house 2400 square feet
  • 5 bedroom house 2600 square feet
  • and 200 square feet for each additional bedroom.

When I test drove the Yukon, I was initially somewhat unimpressed. Having been paying so much attention to higher efficiency vehicles for so long, 21 MPG seems abysmally poor to me, though I have since found that a Toyota Camry V6 has the same combined efficiency. But to put it in comparison with the scale for house size, the full-size SUV, big as it is, seems less of a monstrosity than the gigantic McMansions do.

If the Prius, with a 1254 kilogram curb weight, corresponds with an efficient, 1270 square foot (7 point LEED-H bonus adjustment) 3-bedroom house, then the Yukon, with a 2513 kilogram curb weight would correspond with a 2550 square foot (5 point LEED-H penalty) house. That’s within the realm of reasonableness. It’s not so far out of scale with what an ordinary family might need or use to render the hybrid features an absurd affectation. For comparison, that 15,000 square foot house corresponds fairly well with a 40-foot Winnebago motor home (15,500 kilograms).

Relative size is a factor to consider when evaluating the greenness of anything. There may be any number of good, valid reasons to have something that is larger than average. Lots of good homes can be built with green features that fall within the guidelines of LEED-H. LEED, after all, stands for Leadership in Energy and Environmental Design. A 15,000 square foot house may be green, but it is not leading; it is not setting an example for other green homes. And unless it meets a higher standard in many other ways, it certainly does not deserve LEED certification.

USGBC LEED-H Draft (pdf)
Jetson Green
Lloyd Alter in TreeHugger

image source: Wikimedia