What about a clerestory for natural light? Just raise the ridge 2 ft and put in a row of
vertical windows; facing south gets most light, some heat gain, which is nice in winter,
but may be undesirable in summer. North facing clerestory will pick up natural sky light on
a bright day, no heat gain in summer, OR WINTER
If you are planning on a flat ceiling,
then this changes the roof structure, requires open light path.
The extra cost for three phase is more wires and more sections in a transformer. Gas is great for
heating but I am 900 ft from gas line, they want something like $9 a foot to put in a gas line to
house. Nope, will stick with the propane rather than pay $8K "entry fee" for gas.
Yes, yes, yes to the southern exposure for parking area, man door area to melt off snow naturally.
Solar thermal or solar electric? I have designed both, power my cabin in Colorado by solar electric,
no power bills since '95.....BUT you have to offload all serious loads to propane, or wood, or whatever
and leave solar electric for stuff that has to be electric like lights and computers, etc. You CAN power
bigger stuff but charge for panels and batteries, and inverters gets pretty steep pretty quickly. I have
a 1 KVA inverter in cabin, adequate for my needs.
"Stuff" acts like a gas....expands to fill available volume.
Adding more square footage to start is far,
far cheaper than adding it later. I would consider calculating your needs and at least adding 25%, if funding
will stretch that far.
Bill