Insulation costs $1.00 to $4.50 per square foot installed, depending on the type, location, and R-value. Spray foam and rigid foam boards cost more than standard fiberglass batt insulation. Common locations in a home that require insulation include:

• Attics
• Basements
• Ceilings
• Crawl spaces
• Garages
• HVAC piping
• Wall cavities

Attic insulation costs $1 to $4 per square foot installed or $500 to $6,000 total, depending on the attic size and insulation type. Common attic insulation types are blown-in, batt and roll, loose-fill, and spray foam.

Unvented attics should be insulated beneath the roof deck with rigid foam, spray foam, or reflective insulation. Vented attics should be insulated with batt and roll, blown-in, or spray foam.

Insulation is worth it because it improves energy efficiency. Proper insulation may reduce utility costs by 10% to 40%, depending on the home's location, current insulation level, and insulation type. Many older homes are under-insulated.

The best type of insulation used depends on the location:

• Attics should use blown-in, batt and roll, or spray foam.
• Basements should use rigid foam or flame-resistant batts.
• Ceilings should use blown-in, batt and roll, or spray foam.
• Crawl spaces should use rigid foam, batt and roll (in unvented spaces only), or spray foam.
• Existing walls should use blown-in or injection foam.
• New walls should use batt and roll, rigid foam, or spray foam.

You may need new insulation if your utility bills have risen or your home has damage from:

• Water
• Fire
• Pests
• Mold

You can add new insulation on top of old insulation unless it is wet or damaged by mold, mildew, or pests. If you choose to layer new insulation over old insulation, use blown-in or batt and roll. Older homes may have less insulation than the current standard, so adding more insulation may save money in energy costs in the long run.

Start by searching our list of professional insulation contractors, then:

• Get at least three free estimates to compare.
• Read reviews and browse previous work on HomeGuide and Google.
• Choose a company that is licensed, bonded, and experienced.
• Verify their insurance, warranty, and guarantees.
• Get a detailed estimate, contract, and warranty in writing before work begins.
• Avoid making large payments up front and come up with a payment schedule instead.

After asking questions and verifying their credentials, hire the best insulation company in your area.

When looking for local insulation companies, consider asking the following questions:

• How long have you been in business?
• Are you licensed, insured, and bonded?
• What type of insulation and R-value would you recommend for me?
• What personal protective equipment do you wear?
• How long will this project take?
• Will this job need an inspection or permit? If so, will you handle that?
• What does your warranty include?
• Can you give me a written estimate and contract?