Get the 36-page Energy Savers booklet from your own US goverment today. I assume these energy cost cutters work in other countries as well. This easy-to-read, comprehensive, 36-page booklet is available for download (pdf) or order a hardcopy.

One tip led me to discover and remedy two air leaks around the front door. Plus the house has a nice incense smell (read the booklet and you'll understand).