quicksandfarmer
Elite Member
You mentioned energy efficiency. Since you didn't say where you are in the country, I'll limit my reply to my area of East Texas. Here, we focus on the heat and humidity. Winter isn't very bad and doesn't last very long. Our minimum R value for ceilings is R45, but if you add a little more, you can max it out at R60. I think that the best return on money in a house is attic insulation. Second most important thing is air sealing the walls. Windows are where the most air gets into the house since they are rarely sealed properly. House wrap needs to be taped, but Zip System with Zip Tape is even better.
Something I really hate is when the HVAC system is installed in the attic. Once insulation is blown into the attic, you should never, EVER, go up there. Every time somebody walks, or crawls through the insulation, it's like cracking a window and leaving it open. HVAC systems need regular attention. Some have the filters on the unit in the attic that need to be changed. All of them require bleach in the drain lines every month to keep them clear from sludge building up inside the lines. There is a time when people get too old to climb into their attic to do this, and that's usually when somebody like me gets called in to repair the ceiling because the drain line is plugged, and the pan overflowed and destroyed the ceiling inside the house.
If you don't live in an area with strict code enforcement, or haven't built in a while, you may be shocked by the insulation and air-sealing requirements that are now in the IRC. It's for the good and it's not just about saving money, tight houses are quieter, more evenly conditioned, less dusty and overall just more comfortable. Even if your area doesn't require it, seek out someone who is going to air-seal and insulate the house to a modern standard. Whatever you do, don't go with some foam jockey who wants to spray the inside with a couple inches of foam and says that's good enough. You can do better and it doesn't cost that much.
Many places now interpret the code as not allowing HVAC in unconditioned spaces like attics. In a new build I would put all the HVAC, including the ductwork, inside the building envelope. There's no reason not to.
Which brings up an important point: in a modern house, the insulation and HVAC shouldn't be things you add on after the house is framed, they should be designed in from the beginning. It doesn't cost any more to design in space for insulation and mechanicals and you end up with a much better house.
I would recommend going to a website that specializes in building performance, like GreenBuildingAdvisor.com, and asking there about recommendations on energy efficiency.