It helps a great deal when your major metropolitan areas are located in extremely temperate areas.
- How many heating-degree days are there in the Los Angeles or San Francisco metro areas?
- - Now compare that to say, the top 2 metro areas in the rest of the country.
- How much cooling demand is there in the LA and SF areas?
- - Compare THAT to the same 2 metro areas.
I have lived in the SF Bay area, in a home that did not even have an air conditioner. We almost never needed the furnace in 4 years of living there.
Energy efficiency is easy when you don't actually NEED any.