–By Teresa Burney

See pictures of post-Katrina New Orleans

It would seem like a question I could answer after spending three days at the National Association of Home Builders Green Building Conference, not to mention several years as a student of the topic.

"What is green building?"

But faced with that question from friends and colleagues, I find myself blathering answers that go something like this: "Well, insulation is important." Or: "Recycled materials or materials that can be recycled are good." Or: "Energy efficiency is a key component."

I feel a little less like an incoherent rube after looking at my notes from the event. The fact is that nobody I talked to at the conference--or who lead any of the seminars I attended--could come up with one clear, succinct definition. In fact, a fair amount of time at every seminar I attended involved people postulating definitions only to discard them as being piecemeal explanations of what green building is.

It's even difficult to answer the question about whether certain products are green. Most manufacturers of the product would say that vinyl siding is green, a thought that many old school students of green would discard since it's made from petroleum-based products. But the argument goes that it has a long lifespan and is low maintenance, requiring no painting.

While the definition of green is elusive, I can say that there are some principles of green that can help builders and consumers start to pin down the concept. But even they come with caveats.

For instance, using products made from renewable resources is said to be a green practice--trees versus things made from dead dinosaur goo.

But what if what the vinyl siding folks say--that lifespan and costs of maintenance can make that product as green as or greener than wood-product siding--is true?

Or the idea that carpet made of nylon can be green if the manufacturer can recycle it back into nylon carpet with an expenditure of energy equal to the costs of making it from virgin nylon.

Even using some types of wood is decidedly not green. Clear-cutting slow-growing, old-growth trees from a rainforest and transporting the wood half a world away, for instance, doesn't seem green to me.

Recycling has been heralded as a good thing. But what is the cost of the process in terms of resources? And, if it eventually ends up in a landfill, what is gained?

There are a few things that seem to be irrefutably important if you want to be a green builder, however. Insulating a house well and carefully to decrease energy costs is well worth its cost, as is warding off potential health issues made worse by tight houses through the use of products that don't emit harmful gases and by providing exactly the right kind of ventilation through properly sizing HVAC systems.

Consider transportation and packaging when you make buying decisions. Even if the price tag is the same, the energy costs and environmental impacts of transporting an item a long way has other costs. One thing brought up in a seminar is that anything that requires petroleum puts money in economies far away from home--unless you live in Texas, I guess--rather than keeping the dollars local where they might be recirculated and multiplied several times.

Packaging, too, can be a big waste of resources. Dell Computer saves costs of raw materials and labor by ordering hard drives packaged in one big box on a pallet rather than in individual packages that have to be opened and then discarded or recycled.

In the end, defining green building may be like defining pornography--difficult. But in one very clear instance during my New Orleans visit I knew green building for sure when I saw it.

On the trade show floor, I came across Thomas Dutel, a general contractor sitting on a beautiful heart pine bench, who had developed a new calling after Katrina--dumpster diver for wood.

"I'm like Sanford and Son," said Dutel. He drives the streets of New Orleans picking up discarded heart pine and other old-growth lumber that can't be found anymore that is pulled from demolished buildings and on its way to landfills.

Dutel takes it home, runs it through the planer his wife gave him for his birthday, and turns it into fireplace mantels, new flooring, shutters, and benches.

"I can rebuild an old house where it is brand new again with old-time components," he said.