What's the Real Payoff?

I read an article today that said Al Gore has completed renovations on his Tennessee home. The improvements are designed to make his home more energy efficient by adding florescent or LED lighting, solar panels and geothermal energy.

You may remember that Gore was previously criticized for preaching about global warming while having a highly inefficient house. I really don't know when the renovation started, so I'm not going to say whether or not the upgrades were motivated by this criticism. I am going to question the payoff though.

The article claims that his house is about 11% more efficient than it was before. On the surface, this is saying that it will take about ten years for the increased efficiency to pay for itself. But there's a little more to it than this...

There is the energy cost to manufacture, transport and install these upgrades. The lighting is probably a no-brainer, because the old bulbs are low-cost commodity items, and there's no real cost differentiation. But I'm not so sure about the solar stuff and especially the geothermal stuff. Specifically I'm picturing all of the contractors' vehicles, and the construction vehicles digging up the dirt and so forth. I wonder how many gallons of fuel that costs, and how much that increases the payoff time. I'm not trying to bash on Gore's decision... just curious.