Improving your home's efficiency doesn't have to mean hours in the attic tearing out the insulation. It might be as simple as giving your dear old water heater a warm hug. Wrapping your heater in an insulated blanket—one costs about $10 to $20 at home centers—could save your household about 250 lbs. in CO2 emissions annually. Most water heaters more than five years old are constantly losing heat and wasting energy because they lack internal insulation. If the surface feels warm to the touch, get your heater an extra blankie. You'll both feel better.