It should be noted that just about all information that conveys how you can make your home more energy efficient, is referring to newer homes built on a slab foundation. A homeowner should be aware that there are additional issues that need to be addressed, if your house is on a raised foundation; has a "crawl space". A basic building block in creating energy efficiency, is to start with balanced air flow within the house. Leaks allowing the elements to come in or controlled air out, can greatly reduce the efficiency. One should consider how much efficiency loss they may have, if they don't properly seal off a crawl space. "Like trying to carry water in a paper bag".
Additionally, if the property in question is in California, foundation settlement can be frequent as a result of earthquakes. This can cause doors and windows to become unaligned and create a leaky home. Bolting the foundation before trying to correct a leaky house is a good idea.
Certified Green Real Estate Professional