Good evening! We're trying to choose between broad options to reduce our overall electric bill (wind turbines, solar photovoltaic cells) or focused options to reduce individual components of our electric bill (geothermal heating, higher quality windows and doors, solar water heating, tube skylights).

If we chose every option, we would need ~$80,000; we have ~$24,000. We've researched numerous websites, but have not found one resource that outlines which individual option provides the highest return relative to other energy efficiency options. Most of the information we've seen only relates one energy efficiency option to its not-so-energy-efficient compliment (such as how much more efficient a low-e window is compared to a window without low-e coating).

Considering our limited knowledge and limited budget, how could we rank these choices?

Thanks for any help!

St. Louis