Is Sustainable Design Avant-Garde?

Is sustainable design, or ecological architecture more specifically, a kind of avant-garde?

I don’t mean to ask if it is fashionable, which it certainly is, but whether sustainable design is understood only in terms of new advances or breakthroughs, according to the military metaphor that has come to define the arts more generally?

What I mean more specifically is that as previous “advances” like storm windows, wall insulation, or low-flush toilets, become normal practice, sustainable or environmental design is effectively designated as those practices that are not yet normal. This would mean that environmental designers are by definition marginal or pioneering practitioners, much like successful artists or scientists.

Is this a problem?