I am getting ready to buy a house that is approximately 40 years old. It is a brick one-story on a (steeply?) sloped yard with a huge walk-in crawlspace that is at least 7 to 8 feet high. The home is located in coastal Virginia which is a very hot and humid climate in the summer but can also get fairly cold in the winter with a number of nights in the teens and 20s. I plan on completely renovating it and would like some ideas for the best bang for the buck when it comes to green ideas. A geothermal system is awfully tempting but it sounds like they are very expensive. Then I thought that maybe simply enclosing the unit in the crawlspace would allow for some of the same benefits as a geothermal system. I am definitely going to replace the windows and I'm trying to decide between a good energy-efficient window and perhaps impact resistant windows. Then there is the dilemma of deciding whether to get windows that keep the heat out in the summer and reduce AC bills, or ones that allows heat in during the winter to lower heating costs. How about insulation? If you were going to live in a house like this and try to make it as energy efficient as possible to retire in what would you do? Thanks!!!