On a lot of the land auctions the seller checks the “buyer must pick up item” box. 
Well, the home is my design. I am using Lightwave and will produce the construction drawings from there, using old fashioned drafting. Lightwave renderings coming soon for y’all! Passive is one thing, but active control is another. I am planning robotic movable blinds that deflect or absorb the sun as needed. House as organism.
OK, it sounds like you have researched this matter, and it’s entirely possible that tax on a property will go down. But if the previous landowner had owned it for many years, his tax increase was capped at a small yearly amount, typically much less than the general rate. Then when he sells it, the property is revalued and the new owner gets a shock.
I had some residential property in L.A. that I purchased prior to the Prop. 13 law. Taxes on it were less than $100 per year until I sold it 25 years after purchase. The new owner got a yearly tax bill of $2000 even though the property hadn’t been improved or changed.
In your case, it looks like the previous owner didn’t have ownership for long, or else the Jarvis-Gann amendment has been modified.
The Solar Living Source book I refered too isn’t just about pasive design. It’s more about EV and wind power. But of course they take everything into effect.
Lots of charts and formulas to figure out just what you need. It’s got a bit of everything, including equipment from different manufacturers for sale.
Was that the one on disk? If so, I already ordered it. Just haven’t given it a look yet. I think I have it on my desk somewhere. Give me a couple of weeks, and I might even be able to find it. 
Congrats! Though you’re no longer a Wanderer, I hope you’ll still be Happy