Despite the silly hippy name, you might want to learn a bit about the houses known as Earthships if you don't know anything about them yet. I say this because they've been building these for a while, and they have some of the same goals of sustainability and using recycled materials. I'm not suggesting that you can just copy one of those, but you may glean some useful information. I first learned about them when I watched the documentary Garbage Warrior.
While the hippy ethos of the builders doesn't entirely resonate with me, I think one of the basic notions (as I understood it) is quite insightful, which, as a scientist, I interpreted this way: Rather than trying to use appliances and special materials to make a standard house maintain a comfortable environment, the house should be re-designed around that goal. A typical house is coupled to 3 temperature reservoirs, the sun, the air, and the ground. The temperature of the air is time dependent and so is the coupling to the sun. Each changes primarily on two time scales, diurnal (24 hr) and annual (365 days). Often in a normal house these factors don't get too much consideration, other than an attempt to limit the coupling to the air so that active heating and cooling can be effective. As a result, without active heating and cooling the temperature will fluctuate in time (on both time scales) and will often be uncomfortable (or even dangerous). You can improve the system by increasing the efficiency of the heating and cooling systems; however, it's better to alleviate the need.
The basic approach of the earth ships is to increase the heat capacity of the house to limit temperature fluctuations on the short, diurnal time scale, and then try to keep the time-averaged heating approximately constant on the annual time scale. At any instant it should be possible to use the 3 temperature reservoirs to reach an acceptable steady state, since the ground is cooler that the target temperature (10-15 C a couple meters below the surface) and the photosphere of the sun is hotter (approx. 5500 C). The remaining problem is to balance the coupling to each. To make a long story short, with appropriate use of south facing windows you can make it so your time-averaged coupling to the sun it high in winter and low in summer, to counter the variations in heating from the ambient air. And then you just balance coupling to the sun (hot) and ground (cold) until you have an acceptable steady state.
Of course, that's not quite the way they presented it...