Most of these new houses built in this new millennium are crap!!! Built buy nonunion contractors for the lowest bid, shortcuts on materials, not energy efficient. You REALLY need to do your home work on how homes are constructed, what codes are in the area, and WHO built the home. Get a good INDEPENDENT inspection and appraisal. At the end of the day, it may be worth it buy a new home, and be involved with the decision making, as far as energy efficiency (insulation, ventilation, hvac,foundation, etc).
For instance, before the foundation is poured, adding 2" foam board between the ground and the cement can add r-value to that floor by creating a thermal break.
Or that most homes are only insulated on the corners with 1/2" foam board, instead of all of the walls (in most areas, its code to just do the corners). Fiberglass insulation (rolled or batts) is ideal. Stay away from cellulose blow in insulation for walls, it settles after a few years. Spray foam is the best way, but way more expensive.
You could waste $100's if not $1000's a year in energy bills through poor insulation, cheap windows and doors, or poorly designed HVAC systems.
I say all this to say; just do your homework, don't be afraid to ask questions, and don't make a hasty decision based on overall appearances.
