I'm not familiar with insulating ratings anywhere but here in the US, so I'll do the best I can. I have R39 in the space between the ceiling and the roof. The roof itself is white to reflect most of the incoming heat. This makes it a problem to work on the roof at certain times since your pupils slam shut and you can't see when you climb down. Yes, this is with sunglasses. Maybe I should use a welding helmet? The walls are around R30, but I can't give an exact number since I had them beef up the insulation a lot during construction. The floor is a concrete slab setting right on the dirt. That may have been a bit of a mistake, but it does hold the cool for a long time during the day. However, in the peak of summer I can tell about a 10F difference from the center of a room to the edge where the sun is shining. The floor near the outside walls actually feels warm. Its funny how the floor actually feels warmer than the walls, but I didn't insulate the darn floor. Granted, it's probably 160F or so on that wall, so I have to make some allowances.
I did look into solar cells. I really, really looked into solar cells. The thing is that the lease option we have here is carefully sized to give the maximum benefit to the solar company, not the customer. If I buy them outright, it costs U$5 a watt. So a 60 watt bulb will cost me U$300 dollars in solar cells. And that 5 bucks is AFTER all the rebates and crap. I'd love to do it, especially here in Aridzona, but I just can't see giving them that much money. See, my A/C unit runs around 6800W in the summer (and cold winter); do the math and you'll see how long it would take to break even on a purchase like that. Plus, I have a lot of little loads like freezer, refrigerator, you know, the usual stuff. I do plan on using solar cells to power my battery float chargers (when I finally get them working). I'll get about 50W worth and set them up on a pole by my barn.
My latest energy related project is drop down shades on the patios to cut down on the sun hitting the windows there. Did you know a basic 10' roll up shade for outdoor use can cost as much as U$120 at one of the local home improvement stores. The price depends a lot on how much shade (percentage of sun passed through) and material, but they're expensive. Adding insult to injury, if you want a custom size, like 11 feet, the price shoots up like a rocket. Naturally, I need 9 feet 6 inches for one of them and 15 feet 4 for another.....sigh. So, shade cloth, PVC tubing, polypropylene clothes line, and pulleys here I come.
Meanwhile, my 317s are on order. They're cheap enough to try and see what happens. When I have conquered the float charger, I'm going to start on a larger one to recover a battery that has been mistreated. I'll get one of those great big chargers and smarten it up a whole lot. I thought about that for the float chargers, measure the voltage with a divider hooked to an arduino and adjust the output voltage to supply the current in stages. That seemed overkill for a float charger, but I may revisit that if the 317s give me too much trouble.