So I'm looking to get out of apartment living in the next couple of years, so I browse housing listings semi-frequently just to get an idea of what's out there and what I can expect cost wise.

My boss made an offhand comment about buying a lot and getting a prefab installed on it, so I started looking into it, but I came back with a lot of questions.

1. Home builders seem to have preset floor plans. Every time I try and find a prefab house, all I can find are blueprints for purchase. Do you find a plan you like and then find someone to build it?

2. Home builders I find all build giant houses. I always see comments online about how "Builders can't build affordable homes because of red tape," but I don't understand how that means they can only build 5B/3Ba houses. I cannot find anyone that has preset plans for a 2B house.

3. How much about getting a lot "ready" would be up to me vs a builder? Is that gonna depend on the builder and what they offer? Is that all done out of pocket, or would that be included in the construction loan?

For reference, I'm in Atlanta, though I imagine a lot of these answers will be "It depends on the builder."

I'm looking into insulating the attic above a closed-in back porch & the estimate also included adding additional insulation on top of the blown-in in the attic.

What kinds of factors can be used to think about the value of additional insulation?

For reference, I'm in Florida & keep setpoint around 80 degrees F most of the time when home, and 86 when not home. Power bills in the summer are in the $150-$180 USD range.

It's currently R27 and the quote is to add R11 to bring it up to R38. Code here appears to put new construction at R38 as a minimum, but looking at some charts - it looks like I might have already hit diminishing returns?

This chart I found on "Energy Vanguard" seems to suggest that going from 27 to 38 isn't much of a difference.

Does anyone else have any insight on when those diminishing returns are hit, and if it can make any appreciable difference in power bills? The house itself is comfortable enough, without large swings in temperature.