Many builders are calling themselves green builders now. Some are green; some are barely green-washed.
If you are buying a finished home from a builder, green or not, insist on blower door and duct leakage tests if they have not been done.
Actually, I think a good green builder would present you with a HERS rating for your new home without being asked. But if he/she does not have a HERS rating, ask the builder blower door and duct leakage tests by an independent auditor of your choice.
Start here: A HERS score of 100 is a home built to code. I think you want a home that is more energy-efficient than code.
Put it in writing and Insist on seeing and understanding these scores before signing a contract for a new home, then do not close on the home until the builder has satisfied you for energy-efficiency.
For further information about Energy Audits or Renewable Energy inthis area of Texas contact