Can huge homes be sustainable?

seattle houses 2, originally uploaded by seewhy.

Here's an interesting juxtaposition of a modern home built as infill, adjacent to a typical neighborhood Craftsman home in West Seattle, near Alki. Though I approve of building a modern home rather than a fake "old house", I would like to see it smaller and keeping with the scale of the neighborhood. Cheaper and more efficient to heat equals better for the environment and better for the neighborhood.