Removing old attic insulation costs $1 to $2 per square foot or $1,600 to $3,600 total on average. However, your total cost will depend on the size of your attic and the type, amount, and condition of the insulation. If you're adding new insulation after removing the old materials, the combined cost ranges from $2 to $6 per square foot.

Yes, there are several scenarios where you should remove old insulation before installing new insulation. Remove old insulation if it's damaged by moisture, mold, fire, or pests. Otherwise, these issues can contaminate your fresh insulation and drastically reduce its lifespan.

Removing the old insulation materials before adding new insulation also allows access to the entire space, exposing any underlying issues that may otherwise go unnoticed and result in more costly repairs down the road. This open space also makes it easier to seal off any unsealed penetrations to improve efficiency.

Removing old attic insulation takes anywhere from 4 hours to several days, depending on the insulation type, the attic’s size, and the job complexity. If the insulation is not damaged, professionals can typically complete the job in less than a day. However, if you're dealing with moisture damage, mold, or a pest infestation, the removal process may take much longer.

The lifespan of attic insulation ranges from 20 to 100 years. The type of insulation and the environmental conditions in the attic have a significant impact on its longevity.

• Fiberglass insulation lasts 80 to 100 years in ideal conditions. You should inspect the insulation after 15 to 20 years to ensure that the R-value still complies with current building codes.
• Cellulose insulation lasts 20 to 30 years but typically starts to degrade around the 15-year mark. You may need to add more insulation over time or replace it sooner.
• Spray foam insulation on an attic floor can last 80 years or more when installed correctly and left undisturbed. It lasts up to 30 years when applied to the underside of the roof deck.

The best insulation varies depending on your specific needs and budget. If you're looking for the most cost effective options, fiberglass and cellulose are popular choices for attic insulation and both perform well in most cases. If you're focused on performance and have more room in your budget, consider spray foam insulation instead.

Follow these guidelines when searching for attic insulation removal companies near you:

• Look for licensed professionals specializing in insulation removal and replacement.
• Read through their reviews on HomeGuide and Google.
• Choose a company that's insured, bonded, and has been in business for 5+ years.
• Request an in-person estimate. This allows them to give a more accurate quote based on your attic's specific requirements.
• Get 3 to 5 estimates with similar details to compare.
• Ask for a list of references that you can contact for feedback.
• Get a detailed contract and warranty in hand before they begin working.
• Don't make the last payment before the job is complete. 

Asking the following questions will help you choose a qualified and trustworthy contractor for your needs and budget:

• Is the company licensed, bonded, and insured in this state?
• How long have you been in business in this area?
• Can you provide a list of references I can contact?
• Do you offer free in-person estimates?
• Can you provide a detailed breakdown of what the estimate includes?
• Do you have the proper equipment and expertise to handle mold, asbestos, or pests if you find them? How much do these problems add to the cost?
• How long do you estimate the job will take?
• Do you offer a warranty? If so, what does it include?