Blown-in insulation is one of the most common ways to insulate the attic, crawl space, or walls of a home. The average cost is about $1,351, with most homeowners spending between $891 and $1,893, but this is dependent on whether the work is done by the homeowner or by a professional.ecause insulating walls and floors with blown-in insulation is more time-consuming and labor-intensive, the complete job will total between $1,200 and $1,800, a grand total that might make some want to complete it themselves, no matter the time it takes them.