That's because of the solar panels on the metal roof. The geothermal system circulates water through a pipe 250 feet underground, where the temperature is a constant 55 degrees. It takes far less energy than a normal air conditioning system to reach the desired temperature. These energy efficiencies cost about five percent more up front. I think it's a new thing.
Builders get in a habit of building a certain way.
It's very hard to change something that's so entrenched. As energy costs go up, there's a good chance, people will. Energy efficient homes also help to clean the air. The less we need electricity produced by power plants, the less pollution we create.