I look at it more from an economic perspective, anyway. I work in the energy & sustainability space, and various energy efficiency, energy management, and renewable energy technologies are all very economic in most parts of the country.
It might surprise you to know that a few years ago when the construction industry was in shambles and there was a proposed gov't program humorously called "cash for caulkers", I [as a pretty fervent libertarian] actually thought it was a really good targeted economic stimulus package. It had all of the following positive elements:
1) Many people don't live in their houses long enough for energy efficiency improvements to pay for themselves, and energy efficiency is not heavily valued in the home resale market enough to recoup investment upon sale. Thus, the net aggregate spending on energy efficiency is lower than would make sense if people stayed in a house long-term, making it a perfect opportunity for a subsidy.
2) Homes are durable goods, so the life cycle of many energy efficiency improvements is very long-term.
3) At the time, the people hardest hit by the recession were those in the construction/building trades. This would have been a great targeted way to get those people some work while the housing crisis worked itself through.
Lack of energy efficiency is a negative externality caused by high retrofit costs and a long payback horizon. If there was ever a reason to suggest that gov't subsidy might actually make sense, this is a perfect example.
Instead, the gov't decided to throw money into "cash for clunkers", destroying assets which increased the sale price of older used cars [thus hurting the low-income] in order to prop up the auto industry so that the people who weren't impacted by the recession could buy shiny new vehicles. Stupidity.