I think there’s a lot of value to the conservation angle of the green movement. In general, it’s a matter of efficiency–if you can heat/light/whatever your house with the same quality of life, using less energy and fewer resources, that’s a win for everyone. This applies to a whole lot of things beyond just eco-concerns, however. Conserving heat when you’re cold, conserving energy when you’re running a marathon, conserving your dollars when making a budget–all good ideas. Cut down, conserve, reuse when you can.