Looks like a duck...

If we were driving past this house, we wouldn't think twice about its functionality, but it's actually a Passivhaus! Passive houses, more commonly smaller and boxy in design, are constructed to be essentially air-tight with special windows and ventilation systems to heat the interior and minimize energy loss. According to the Passive House Institute US, a Passive House can save up to 90% of space heating costs compared to a conventional house. This one in particular reportedly uses 70% less energy than a conventional Northern California home! So it's a little out of our price range... but we can dream, right?

Read more on this inconspicuously green home from Treehugger.