My wife and I are in the process of designing our home in Houston, and it willbe about 4300 sq ( the mcmansion we did not want ). this forum has been great with details, but looking at the big picture on roi for energy efficiency and comfort. in my climate, does it make sense to go from our builder base selections to the following upgrades.
1. 14 seer ac to 16 seer or above ac
2. 80% energy efficiency furnace to 90% or above
3. the ducts are insulated at r-6, should insulate more
4. does it make sense to go from aluminum to vinyl windows, or should i just look at the u-factor and solar heat coefficient.
5. tankless water heater or higher efficiency traditional water heater or solar water heater.
6. we are considering icynene insulation. thoughts? what are the hvac considerations in a totally sealed home.