Eco (Being green): Sustainability for the long run means having a structure that: 1) won't fall down; 2) is water-tight; 3) costs little to heat and cool. The new roof addresses the first two of these three by keeping water out of the wooden frame to ensure durability. The insulation and solar hot water satisfy the third criteria.
Thrifty (Being penny-wise): Economic sustainability means investing in systems that will persevere. As a comparison, I offer the boom and bust economic cycles of "bubble" investments that we've witnessed over the last few decades. These are patently unsustainable and risky. In contrast, our solar hot water system offers about a 7 year payback period which translates to a 10% annual return (banker's rule of 7). As energy prices continue to outpace the rate of inflation, that payback period shortens and our virtual "rate of return" increases. The same can be said for insulation, although I don't know the specific payback period.
Conservative (Being cautious): As energy prices continue to rise, not only the cost of heating and cooling will rise, but also the price of all materials made using energy. This include virtually everything we buy: food, clothes, insulation and iron roofs. Buy purchasing the highest quality roofing material and coating, we are hedging against future price rises. In other words, our roof will last longer than a cheaper one and not need to be replaced as often. This will save on both future materials and labour costs.
This is not a flash reno nor a "Grand Design." On the contrary, it is patently humble. But by investing in high quality, durable, energy efficient products, we are able to be eco, thrifty and conservative. Come to think of it, this is all about being conservative: conserving energy; conserving resources; conserving money. You'd think we vote National (NZ) or Republican (USA) with our extreme conservatism!
What will it take to get John Key and John Boehner to embrace these types of conservatism too?