I want to express a huge thank you to the many knowledgeable contributors who make the forums at GBT such a valuable resource. The simplest form of my question is if there are any folks in the San Francisco Bay Area that you recommend for advice/consultation on improving the energy efficiency of my 1971 house. The more complex form involves more information.

I'm in 94025 - climate zone 3, typically wet winters and dry otherwise. The most extreme temperatures are in Dec or Jan, but even then heating degree days are only in the 550 per month range. CA has high natural gas and electricity costs, but at current rates, I will pay $600 in gas for the winter season for heat and $0 in summer for cooling. Heat is copper radiant in the slab and there is no AC.

My house was built in 1971 - 2600 living sq ft with an attached garage and a large center (open) atrium. It is a single story, mid-century modern design, build and sold by Joe Eichler. I love it, and, can't imagine moving, but it has an extreme amount of single pain glazing. There are 11 sliding glass doors and plenty of windows. And, it was certainly designed for a time when energy was cheap.

Construction is basic. Slab on grade, post and beam supporting 2" T&G redwood ceiling. 2/3rd of the roof is flat, the center soars with an A shape, creating a __/\__ profile. The roof is now very well insulated, but the (too) thick slab is not at all, either underneath or at the perimeter. The walls have 1971 yellow fiberglass batting with 1 foil side. Siding is redwood T1-11 over tar paper. There are huge overhangs all around the house, creating nice solar gain in the winter and manageable ones in the summer. However, in the winter, the house could easily swing between 70 degrees (afternoon, sunny day in the 60s) and 50 at night with the heat off (40 degree evening).

Given that I have so much glass with so little R-value, I'd guess that I'd get the most comfort and least temp swings by changing to double-pain windows and sliders, but I'd am curious about which of these 4 projects you think would generate the most comfort and temperature control in the winter:

a) replace all the glazing. added benefit is UV control. downside is that it will be very expensive

b) add perimeter slab insulation. this could be combined with a large landscaping project. downside is designing for termite control and it doesn't seem to be common in my region

c) add wall insulation, likely dense-packed cellulose. would probably want to blow from the interior for more seamless repair but everyone seems to do this from the exterior. should help with air leaks without creating moisture problems

d) tear off siding, add both insulation and house wrap. big downside here is that no one makes redwood T1-11 anymore, and, even though current siding is in great shape thanks to climate and large overhangs, hard to believe that removing it wouldn't create a lot of damage. a benefit here is that it would be easy to accomplish some seismic upgrades

So, if you have read this far, thank you. I'd love your advise. ROI isn't a huge deal as I suspect none of the 4 would ever pencil out, but it would be great to get the GBT perspective. I'd guess from least to most expensive they rank: C, B, D, A, so I'd also love to know any downside about dense packing both from the interior and with existing insulation.