Get an INSTANT, detailed estimate of the cost to Insulate an Attic! Our free calculator uses up-to-date, trusted data to estimate typical subcontractor costs for a Attic Insulation project. For a basic 500 square feet project in zip code 47474, the benchmark cost to Insulate an Attic ranges between $1.59 - $3.08 per square foot* . To estimate costs for your project: 1. Set Project Zip Code Enter the Zip Code for the location where labor is hired and materials purchased.