My previous startup was an API that would give homes an energy efficiency letter grade along with a bill estimate to embedded in real estate websites. While it failed for a host of issues, one that stood out in my head was how little people valued efficiency over renewables.
Generally speaking, money invested in improving building efficiency will have a better carbon and financial payback than any form of solar, wind, or hydro. And yet, homeowners will get solar panels before they insulate their walls.