Insulation, Radiant and Vapor Barriers - Exterior Walls Not Insulated - Thinking of getting blown in....

Hello, our house currently does not have insulation on any exterior walls.. It is very cold by the walls and our heating bill most likely is a lot higher then it could be.

We will be siding our house in the next year or two.

My questions are how much does getting insulation blown in on all exterior walls cost (estimate)? Do they do it by square foot? Will it likely pay for itself over time? How long?

How noticeable is it after they're done and plug the holes?

Thanks for any info.

http://www.eere.energy.gov/consumerinfo/energy_savers/insulation.html

This site will give your the information you want.

http://www.ornl.gov/sci/roofs+walls/insulation/ins_01.html

This site will give you even more information if you want.

Both sites are very good and easy to understand.