When basements are insulated properly they can save you money on heating while providing a comfortable living area. For the most part a basement, with insulated exterior walls should be considered a conditioned space. However, even in a house with an unconditioned basement, the basement is more connected to other living spaces than to the outside, which makes basement wall insulation preferable to ceiling insulation.
Adding insulation on the exterior of the basement walls will:
• Reduce heat loss through the foundation
• Protect the damp-proof coating from damage
• Provide protection against moisture
• Reduce interior temperature swings
• Reduce condensation on surfaces in the basement.
• Conserve your room area, relative to installing insulation on the interior
For more information about insulated basements see http://energy.gov/energysaver/where-insulate-home or call 309-764-2500.