Many homeowners request contractors to bid on an insulation job because they believe adding insulation will improve their comfort issues and help them reduce their utility bills. While the contractor is happy to oblige the client and bid on the job, the homeowner may not always get the desired results. Why? Because most insulation contractors are not educated in building sciences. They do not ask the homeowner questions about their comfort issues and they do not provide diagnostic testing to determine if just adding insulation will solve the customer's issues. Perhaps they are using the wrong product. If the customer asks for insulation, will the contractor provide fiberglass, loose cellulose, dense pack cellulose, foam, rock wool, or something else? Who decides? How is that decision made? Is it strictly a price decision? What R-value should be used? When they install it, are they thinking about air sealing? Did you know that a gap, even as small as 5%, will render the R-value in that area to be HALF as effective? How well insulation is installed is critical to its performance.
My advice to you - hire an insulation contractor that is educated in building sciences.