A study done by the Harvard University School of Public Health estimates 46 Million homes in America are under-insulated. The most commonly under-insulated part of the home is the attic. Energy Star suggests if you can see your floor joists, you are probably under-insulated. Not only does the lack of proper insulation allow heat to escape, the escaping warm air can cause a harmful cycle in which lower layers of snow on your roof may melt and refreeze causing ice damage to your shingles. There are several online resources to help any size home-improvement project, check out RenovateBoston for some more details.