This software is designed by a Government/University team in Canada and the US. I used it to cut my energy loss in the house (and eventually the garage). It lets you test different materials, windows, insulation, shrubbery, fences, etc. and shows the results. Good stuff. This is the latest free version. You should subscribe to get the latest versions. Its used in 222 countries, over 185,000 users! http://www.retscreen.net/ang/home.php
