The national average to insulate a typical home or space costs between $800 to $3,500, including materials and labor. The final cost to install insulation will depend on the type of insulation you choose, your project's total square footage, labor costs, and prep and cleanup work involved.
What's In This Cost Guide?
Insulation keeps your home comfortable year-round. In the winter it keeps warm air from escaping your home, so your home stays warmer. In the summer, it keeps hot air from entering your home, so it stays cooler. It helps your heating and cooling systems work more efficiently, saving you money in energy costs.
The main reasons for new home insulation include:
- Making your home more energy efficient. The attic is the most common space insulation is needed. If you live in an older home, you may need insulation in the wall cavities—the space between the exterior shell and interior perimeter drywall. Spaces between floors and crawl spaces may also benefit from insulation.
- Finishing a space. If you want to create living space from an unfinished basement, you'll need to insulate those walls, too.
- Soundproofing spaces. Home insulation can also keep you comfortable in other ways. It can be used between drywall and floors to soundproof rooms, such as media rooms.
- Preventing roof ice dams. Ice dams occur in climates that get significant snowfall and freezing temperatures. As snow on your home's roof melts, it should flow down your gutters. Inadequate insulation can cause hot and cold spots that cause melting water to clog, forming a dam that pushes water into your attic or ceiling or down your walls. Icicles along your gutters are a telltale sign that your ceiling or attic may need more insulation.
- Problems with existing insulation. You might need new insulation because of unrelated water damage or a pest problem, such as a squirrel or raccoon nest. Old home insulation that's deteriorated may no longer be effective. Deteriorated cellulose fill may also cause fine dust that can leak and disperse throughout your home.
Several factors go into the price for insulation installation. These factors include:
- The project's square footage and the required R-value
- The type of insulation material and any special equipment needed
- Preparation and cleanup costs
For example, spray foam insulation cost varies, but will typically ring in at about 3 to 4 times the cost of fiberglass insulation. Insulation pricing is based on per board foot and required R-value, as well as the prep and cleanup costs of the project.
Insulation's resistance to heat flow, also known as thermal resistance, is measured or rated in R-value. The higher the R-value, the greater the thermal resistance at keeping heat in or out. The R-value, and not the depth of the insulation, is what determines whether your home has adequate insulation.
Several factors will determine the R-value of the insulation you need, including:
- The climate you live in
- Your home's heating and cooling system
- How many rooms or part of the home you want to insulate
In new home construction, local building codes set the minimum R-value required for insulation. If you live in an existing or older home, going by local building codes is a good rule of thumb.
The Department of Energy also has region-specific recommended insulation R-values for your attic, walls, floors, and crawlspaces. These R-values are often higher than building code requirements. For regions in the South, the DOE recommended R-value for attic insulation ranges from R30 to R49. For northern climates, the recommended R-value for attic insulation ranges from R49 to R60.
An insulation professional can help you determine what, if any, additional insulation may be needed to achieve maximum energy efficiency. When adding new insulation on top of old, insulation professionals will need to know the type of existing insulation, its related R-value, and the average depth of that material in the space. If your home's existing insulation is in good shape, new insulation can be installed on top of it to achieve the desired R-value.
Different types of insulation have different R-values. For example:
- Cellulose has an R-value of 3.2 per inch of depth
- Fiberglass has an R-value of 2 to 2.5 per inch of depth
Radiant barriers, however, don't have an inherent R-value. Instead, this type of reflective sheeting reduces summer heat gain by re-emitting radiant heat rather than absorbing it. It's most often used in warm climates, in conjunction with packed insulation, to reduce cooling costs.
Insulation comes in a variety of materials to match your budget and project. Insulation products can be made from cellulose or recycled newsprint, fiberglass, polystyrene, mineral rock or wool, spray foam, even denim.
Insulation professionals will work with you to determine the best insulation for your needs and priorities. The most commonly used insulation products on the market today come in different forms, including:
Batt or Rolled Insulation
Insulation that comes in batts or rolls is among the most economical. It doesn't require special equipment and is generally not as labor intensive as the other types of installation. Batts and rolls come in fiberglass, mineral wool, natural fibers, and plastic fibers. The cost for fiberglass batts, without installation, ranges from $0.12 to $0.16 per square foot for an R-value of 11, to $0.55 to $0.60 per square foot for an R-value of 38.
Also known as loose fill insulation, blown-in insulation comes in three main options: cellulose, fiberglass, and mineral or rock wool. The national average for blown-in insulation costs is between $1,000 and $4,000. The cost to add it to an existing home averages between $800 and $2,000.
Foam Board or Rigid Board
Insulating boards come in polystyrene, polyurethane, and polyisocyanurate and provide a high level of insulation for little thickness. They can be applied to both interior and exterior walls but must be covered with approved materials for fire safety. Closed cell foam insulation boards are often used to cover interior foundation walls in basement remodels.
Spray Foam Insulation
Spray foam insulation can be used in new construction with open and unfinished walls and attic spaces or retrofitted to existing wall space. In finished wall space, contractors must drill two to three holes per 16-inch stud cavity to inject the spray foam.
Expect to pay between $3 to $5 per square foot on average nationwide to have spray foam injected into an existing home. Spray foam costs more to install because of the special equipment, professional labor and materials required. In retrofit cases, contractors often have to repair hundreds of holes in the drywall after the spray foam insulation job is complete.
There are two types of spray foam insulation: open cell and closed cell. The "cell" refers to the small bubbles that make up the foam.
Open cell spray foam insulation consists of bubbles that are deliberately left open. Open cell insulation is softer, less dense, and more flexible than closed cell insulation. Open cell foam insulation typically has an R-value of about 3.5 per inch. It is designed to expand to a thickness of 3 inches, meaning that only one application of open cell insulation is possible in most standard walls.
Closed cell spray foam insulation consists of closed cells. The cells are densely packed to ensure that no air or moisture can penetrate inside the foam. Due to the tightly packed nature of closed cell foam insulation, it is rigid, dense, and is more resistant to pests and moisture than open cell foam insulation. Closed cell spray foam insulation has an R-value of about 6.0 – 7.0 per inch, making it ideal for extreme temperature conditions.
If the insulation contractor needs to remove existing insulation, he may charge a separate removal and disposal fee.
The price to have insulation removed by machine can cost about $1 to $1.10 per square foot.
The price to have insulation hand-removed costs about $1.35 per square foot.
Preparation can also involve fixing other damage to the attic, walls, and other spaces. In cases of water damage and mold, some insulation contractors offer mold remediation before installing the new insulation. The charge will be based on how extensive the repairs and materials needed to make the repairs.
Cleanup costs include disposal of existing insulation and other damaged building materials.
Some insulation contractors provide cost estimates over the phone, based on the project or home's square footage and the age of the home. Ask whether they are basing their recommendation on building code requirements or DOE recommendations or both.
Other insulation contractors offer free in-home consultations and energy audits to determine your home's unique insulation needs. Contractors will come out and measure the condition and depth of any existing insulation. A walk through can also catch problems, such as previous insulation that wasn't installed correctly the first time. Be sure the cost estimate includes a breakdown for prep and cleanup.
- Ask for a free in-home energy audit and cost estimate. You may avoid costly surprises this way.
- Be wary of contractors who provide estimates in inches only. Make sure your cost estimate specifies the type of insulation material, the R-value, and price per square foot.
- Remove the old insulation yourself, if you can get a discount from your contractor. Be sure to check with your local municipality about any proper disposal requirements. You can also ask your contractor whether they can dispose of it for free, or for a small fee.