Brrr! It's getting cold out there. And yikes! Your heating bills are starting to climb sky high. Fortunately, there are ways to stay warm without spending a small fortune or packing up and moving to a sunnier clime. Home insulation is the key to lower winter energy costs, keeping heated air in the house and cold air out. (It helps your house stay more comfortable in summer, as well.) And one of the major areas where you want to limit heat transfer is your roof. Here's how to insulate the roof so your family stays warm and cozy while your energy bills stay under control.