4. Increase insulation. The most significant source of air leaks in the home does not come from the drafts you feel, but from basements and attics, according to Energy Star. Learn how to locate and seal air leaks and improve insulation in the DIY guide available on the Energy Star website.What is Energy Star? Energy Star is a joint program of the EPA and the DOE. Products that meet standards set by these two agencies can earn the Energy Star label.5. Seal holes and cracks. Any deep holes or cracks in your home's walls, ceiling or floors can be a potential source of air leaks. Investing just a few dollars in caulk and weatherstripping (or foam sealant for larger gaps) is one of the easiest and least expensive ways to improve your home's energy efficiency. For more tips on sealing air leaks, visit the DOE's website.