If you decide to hire an insulation contractor, there are a few things to consider to ensure peace of mind and a quality installation job.
To find qualified contractors near you, use this Contractor Locator or contact the Insulation Contractors Association of American (ICAA) at http://www.insulate.org for a list of certified contractors in your area. Ask your friends or neighbors, or your builder, who they recommend.
Always check references to make sure the contractor is reputable and does quality work; and check for any certifications the contractor may have.
Get written cost estimates from more than one contractor. Be sure that you have specified the same R-values and areas of the home to insulate when comparing quotes. If you want Johns Manville Formaldehyde-free™ insulation, be sure to specify that as well.
Make sure that the contractor gives you a signed and dated written contract or receipt for the work and material. By law, this should include: the coverage area, thickness and R-value of the insulation installed for all insulation except loose-fill. For loose-fill, it must also show the number of bags used.
Finally, don't be afraid to inspect the work and demand resolution if something does not look right. Once the drywall is up, you may not have the chance to fix a potentially damaging mistake.