The fact remains that neither of those plans is good for a growing family for many reasons. So if you're planning for a family, you can do better. And neither is particularly conducive to the way I would imagine a couple with no kids will want to use their home. (admitting that I have only been part of that "couple with no kids" demographic for about 10 months lol) There is no room for entertaining friends, the first plan has good space for guest room/hobby rooms/office but the second doesn't. The second plan has a practical guest bathroom. In both plans you need to walk 30 ft before you get to a spot to hang your coat or put down the bottle of wine you brought! And good luck getting shoes on and off in that bottleneck.

Air sealing and insulation is always less expensive in the long run if existing is not great. I agree if you can't improve weatherization. Mini splits a good option if you want an additional zone, but the overheating might easily be fixed with larger ducts, right?

Hi, Suzanne, I can't speak to requirements in your area. Here in Virginia, builders are obligated to comply with the statewide building code and Virginia's statutory warranty requirements for new homes. These are intended mainly to protect the health, safety, and welfare of the general public, and, to a lesser extent to mandate certain energy efficiency/sustainability requirements are met. I submit that it is in both a builder's and homeowner's interest to incorporate a written performance standard in any construction contract. The standard should define quality defects and the specific actions the builder should take to to remedy them. A number of years ago the National Association of Home Builders (NAHB) produced Residential Construction Performance Guidelines for Professional Builders & Remodelers. The NAHB Guidelines are now in their fifth edition. The National Association of State Contractors Licensing Agencies (NASCLA) produced a somewhat similar set of performance guidelines in 2009. In contrast to building codes, these performance guidelines are intended as standards for addressing quality-related issues. Your builder may not be obligated to follow either of the above performance guidelines, but they equip you with a reasonable and actionable quality standard you can use to help argue your point.

Looks larger than 1/8", but maybe that's because it is so close up. Do you have a table saw you can cut off a blade width on the bottom of the tile side? I've used a sander and an exacto knife to trim my base.