• Spending money to put insulation inside your walls or improve the insulation that has been there is like putting a deposit into your savings account. Energy savings over time will collect like dust on an antique chest in the attic when you improve your wall insulation. Besides saving money, you also improve the ability to stay cool during the summer and warm during winter.
  
  

Insulation Inspection

• If you aren't sure whether your walls already have insulation, you've got two options before opening up a wall. Head to the attic if you've got one. If you don't see any insulation there, the chances are pretty good your walls weren't insulated. If you don't have an attic or want additional proof, remove the cover plate on an electrical receptacle on an exterior wall. You should see some signs of insulation installation if it was done according to "Household Survival Manual."
  
  

Expense

• How soon you can expect to recoup energy savings on the initial investment made by insulating walls depends in part upon the construction of the house. Installing insulation inside walls may be significantly more expensive in one house than it would be in another. "Popular Mechanics Complete How-To" recommends avoiding expensive insulation techniques if you don't plan to stay in the house for very long.
  
  

Vapor Barrier

• Insulating walls is much easier when it is done during construction. If this is your situation, be sure to include a vapor barrier in exterior walls. A vapor barrier should be located on the side of the insulation that is warm during the winter.
  
  

Additional Insulation Required

• Insulating your walls will have only a limited effect if you do not also take steps to improve energy efficiency around windows. Glass is simply not a very good insulator, so you can consider adding a layer of glazing or replacing with double-glazed windows, according to "Ortho's Home Improvement Encyclopedia." Also be sure to add caulking and weather stripping where appropriate.
  
  

Efficient Installation

• When installing batt insulation in the wall, you need to resist the natural temptation to compress an item to make it fit within a space. Compression and packing insulation will reduce its effectiveness. "Save Energy, Save Money!" recommends making sure that your batts of insulation completely fills the cavity between studs to attain peak energy efficiency.
  
  

Finished Walls

• Finished walls are best insulated after construction by drilling a hole through the exterior of the house. Through this hole will be blown loose-fill insulation. This is not usually a job for novices looking for a quick DIY project, so seriously consider hiring an experienced professional to insulate your finished walls. In some cases you may be able to blow insulation into walls from the attic as long as access is available to those walls.