Blown in insulation is one of the most common ways to insulate the attic, crawle or walls of a home. The average cost is about $,, with most homeowners spending between $ and $,, but this is dependent on whether the work is done by the homeowner or by a professional..Average cost to insulate an attic is about $, $, , sq.ft. attic, pipes, vents and fans insulated with blown in cellulose . Find here de.ed information about attic insulation costs..Enter the dimensions of your attic. Width ft. Length ft. Desired Insulation Type FiberglCellulose . NOTE Fiberglinsulation can be installed in rolls .ed batts or blown in. Cellulose is loose, blown in material. Adding rolled insulation on top of existing blown in insulation is not recommended..How much home insulation should cost. Average costs and comments from CostHelper’s team of professional journalists and community of users. In order to buy materials or talk to contractors, you need to determine what level of R value, or thermal resistance, you want to achieve in a givene..