[stevehull]

It would sure help if I knew where this home is located . . .

But I would seal the sill plate with silicone caulk even if a layer of "sill seal" is used. Then I would seal up everything you can possibly get your hands on BEFORE sheetrock is put on.

Do everything you can to seal up the house. When you move in consider putting in an air to air heat exchanger to provide ventilation. It would be great if those ducts could be put in during construction.

One area where a huge influence can be done is to seal up the washer/dryer area in a room with a door with good weatherseals (I use outside door frames for this, but use interior doors. Inside this room, put in a duct to the attic. The duct in the attic is sealed up with filters so dust doesn't come in. This allows "make up" air to be used for dryer operation and you don't suck out conditioned air via the dryer. Do not put in any HVAC ducts into this washer/dryer room.

Air that goes out of the house, must come in - and it is outside unconditioned air you have to heat or cool.

A dryer uses about 400-600 ft3 per minute and just 40 minutes of use will cause about 20,000 ft3 of air to be lost to the outside. A 2500 sq ft house with 8 foot ceilings has a total volume of about 20,000 ft3 . . . .

If you have kids, then I bet you are doing a load (or more) or laundry every day. Think about the savings when you don't exhaust all the conditioned air every time you turn on the dryer.

See if T8 bulbs can be put in and dimmers that are compatible with CFLs and/or LEDs.

Can you negotiate to put in a higher SEER AC and a higher efficiency gas furnace at your cost?

You will be rewarded very well for your time and effort.

Good luck!