It's usually worthwhile to add attic insulation, and that can be a practical do it yourself (DIY) project. Before that, however, it's just as important to air seal to reduce air leaks. Insulation must be in full contact with an "air barrier" material to be most effective.
Check behind the face plate of exterior wall outlets to see if you have insulation in the walls. If there is none, there are special products and methods for a trained professional to blow or dense-pack insulation into wall cavities. Whether or not the energy saving and comfort benefits will outweigh the cost depends upon the climate and the type of construction. Another important consideration is making sure that the insulation is protected from getting wet.
One of the best ways to determine if you need to insulate is to hire an energy auditor to come into your home and evaluate the air sealing and insulation levels that are currently present. The auditor will have tools such as an infrared camera that can show temperature differences in walls and ceilings, indicating areas that are lacking insulation. The auditor should also have knowledge of construction materials and practices common in your area. Check with your state energy office or local utility provider for a list of qualified energy auditors in your area. If your area does not have energy auditors, you can evaluate areas of your home with a little effort.
Tips on what to look for and more detailed information about insulation can be found at the link below to the U.S. Department of Energy (DOE) website. The site includes recommended levels of insulation for all areas of the United States as well as some tips concerning insulation and insulating. U.S. DOE Insulation Tips and Recommended Insulation Levels
