The US Green Building Council has released its long-awaited draft of LEED (Leadership in Energy and Environmental Design) standards for homes. LEED-compliant commercial buildings are both remarkably energy-efficient and provide interior environments friendly to workers. With the release of the LEED for Homes draft, developers and homeowners can see what steps are the most critical for making a home a green house.
Technically, what the USGBC has released is a set of guidelines for pilot projects meant to test the utility of the various elements on the LEED for Homes checklist. It's likely that, once the pilot projects are completed and analyzed, the LEED for Homes rules will be modified. These projects will be built in 12 different regions (PDF) in the United States; interestingly, while most locations (including big states like California, Florida and Texas) are covered by single providers, Colorado has three.
Even if you aren't a developer, potential home buyer, or even in the United States, the LEED for Homes guidelines make interesting reading. The Pilot Rating System document (PDF) explains the goals of the LEED for Homes project in more detail, and discusses each item on the LEED for Homes checklist in full. The draft checklist (PDF) itself includes numerous references to issues that we've talked about frequently on WorldChanging, including: site density, permeable pavement, rainwater harvesting, high-efficiency lighting, and more.
It's particularly interesting to see the relative credit scores for different items. Highest rated individual items (not counting "packages"): up to six points for renewable energy use, six points for "very high efficiency fixtures (toilets, showers and faucets)," and up to ten points for "Home that is Smaller than National Average." Those three items alone can put a house 2/3s of the way to LEED certification, presuming that the various "required" features are in place. LEED silver, gold and platinum levels, of course, would need substantially more effort.
These draft guidelines are meant for developers (architects, builders) of new homes only; USGBC indicates that LEED guidelines for retrofits of existing houses could come later. This makes some sense, as developers are in control of many more environmental aspects of a housing community than are homeowners; there's little that a new owner of an old home can do about proximity to green space, for example, or the degree of disruption of pre-existing landscape. As an example of what the LEED for Homes "Existing Home" guideline might cover, compare the basic LEED list for new construction (XLS) with the "LEED-EB" (PDF) guide for existing commercial buildings.
But that doesn't mean that these guides are useless for current homeowners looking for ways to improve the environmental footprint of their houses. Many of the checklist items are applicable to existing dwellings, and some can even be installed without requiring professional assistance. Moreover, the LEED credits give a decent first approximation of which improvements would have the most positive effect, to the planet as well as to one's overall health and long-term finances.
Before the USGBC gets to the "LEED-H-EB" (or whatever they call it) standards, they have another project ahead of them: LEED-ND -- LEED for Neighborhood Development. The information on the idea is extremely limited (PDF), but very intriguing:
LEED for Neighborhood Developments (LEED-ND) would emphasize smart growth aspects of development while still incorporating a selection of the most important green building practices. The scope of what would be considered smart growth design would be guided by the Smart Growth Network’s ten principles of smart growth, and would include density, proximity to transit, mixed use, mixed housing type, and pedestrian- and bicycle- friendly design. LEED-ND would then provide an objective basis on which to certify developments as smart growth. In short, LEED-ND would create a label, as well as a set of guidelines for decision-making, which could serve as a concrete signal of, and incentive for, better location, design, and construction of neighborhoods and buildings. Equally important, it will be a product that can be readily folded into USGBC’s existing and successful efforts to market LEED to developers, consumers, and policymakers.
I find this an exciting development (no pun intended). Buildings are not ecosystems unto themselves; sustainability is even more a function of context than it is of construction. The LEED-ND concept suggests that a day may soon come when not only do we have reliable standards for the sustainable development of homes and businesses, we have real-world-tested guidelines for what makes for sustainable communities, cities and (we can dream, can't we?) megalopolises.
"LEED Guidelines for a Sustainable Megalopolis"
That would be quite the tome, wouldn't it?
LEED for Houses is a heroic effort, and I think the process of pilot testing will improve it greatly. I already can see a few corrections that need to be made. For instance, the "Home that is Smaller than National Average" standard would inflict a maximum penalty on Amory Lovins' house, even though it's one of the most efficient in the U.S. That doesn't make much sense. Besides, people like big houses. If the structures are fully sustainable, why penalize them? Isn't the point of Viridian Green to dispense with the needless self-flagellation and sacrifice that characterizes conventional environmentalism?
The influence of LEED-ND is already apparent in the first section of LEED for Houses, "Location and Linkages." The full LEED-ND checklist will expand on those concepts considerably. Another LEED-ND standard, Housing Diversity, is based on the TND Design Rating System.
The pilot LEED-ND standards will be released very soon. You can join the LEED-ND correspondence committee by emailing firstname.lastname@example.org.
While the draft guidelines would indeed penalize Amory for the size of his home, his house -- no matter how efficient it is now -- would almost certainly be more efficient if it were smaller. Home size is the #1 determinant of efficiency; a stock smaller-than-average house will outdo a bigger-than-average hose filled with Energy Star appliances and building materials pretty much every time.
See, that's the problem with inflexible standards based on abstractions. What if a house -- even a "positively enormous" house -- uses zero net energy, or is even a net energy producer? That whole LEED for Homes square footage analysis falls apart. And zero/positive net energy houses are just the type that are likely to be applying for LEED ratings. Since LEED for Homes is a standard for individual houses, it seems to me applicants should have the option of modeling energy use directly, rather than the square footage calculation.
It's a bit murky. I strongly advocate small homes, but consider: the size and efficiency should be normalized for the number of occupants. Think of 2 houses, each requiring the same power per unit area (in Btu/square foot, watts/square meter or whatever). The smaller one houses 1 person. The larger one, twice the size, houses 4 people. The larger is more efficient in an important way. This is analogous to transport: a bus, when empty, is less efficient than a Prius, but when full, it's a lot more efficient.
Energy use per occupant, and area per occupant, seem like better metrics. Of course, households fluctuate and houses change hands, so this might be too difficult to measure. I hope that LEED didn't water down their analysis just to make measurement easier.
I don't know why the LEED committee choosed the criteria of the size to be So important but I agree with them. For me this goes in amuch larger view of the house. It has to be small (or not huge at least) because it requires less material it need less surface and it makes less urban spreading
Resources used in building materials should be included in the net energy usage calculations, of course. Again I ask, if the structure is fully sustainable, what's the problem? Are you suggesting we have a shortage of rammed earth or straw bale? I also don't think there's necessarily a relationship between house size and sprawl. There are plenty of "positively enormous" condos and townhouses that are located in central cities and that use less energy than small houses in the 'burbs.