I found this article from Greener Buildings interesting. It sounds like a lot of the things that we say to our clients at Green Squared.

The cliff notes version of the lessons:

1. Green building retrofits are truly global.
2. Energy efficient and sustainable retrofits can be remarkably cost-effective.
3. Many of the retrofit approaches with the best paybacks are the simplest.
4. There are also some fascinating technological advances being introduced to the building energy-efficiency market.
5. One of the most intriguing trends is the extensive use of passive heating and cooling
6. Next on the horizon? Net-zero energy buildings-structures

I highly recommend the full article. The author Leanne Tobias is hosting a conference in San Francisco yesterday on commercial building retrofits so if I see a summary or video, I will post it as well.