By Glenda Taylor | Updated Apr 7, 2022 11:37 AM

Insulation is vital for helping keep a home’s interior cool in summer and warm in winter. Still, various insulation products come with different thermal reduction values (R-value), and costs vary. Spray foam insulation is dense, and due to its expanding nature, it seals air gaps more thoroughly than other types of insulation, so it’s among the best options for insulating a home. However, it’s not the cheapest option available.

In general, spray foam insulation cost runs between $1,284 and $3,741 to have it professionally installed, with a national average of $2,492. Unlike other types of insulation, such as blown-in cellulose fibers or fiberglass batts, installing spray foam insulation isn’t a DIY project. Ahead, determine whether spray foam insulation is suitable for your home, and find out what factors will affect the overall cost.

Spray foam insulation is typically composed of a polyurethane-type liquid that, when combined with air, expands to fit in the interior of stud walls as well as rafter and joist spaces. This makes spray foam an excellent sealant because it fills even tiny gaps to reduce air leakage. If you’ve ever lived with drafty windows, you know how difficult it is to heat and cool a house efficiently. The drafts result in running up the energy bills while reducing comfort.

Spray foam insulation is applied in 1-inch-thick layers—and the pros who do this are very good at keeping the layers uniform—but a stud space is deeper than 1 inch. Still, calculating the cost of spray foam insulation is relatively simple.

For open-cell spray foam insulation (see below), filling the wall to a depth of 3.5 inches would cost between $123 and $182. It would cost more to fill the same 80-square-foot wall with closed cell spray foam insulation—between $280 and about $420. Those estimates are arrived at using the costs per board foot for open-cell insulation ($0.44 to $0.65) and the cost range for closed-cell foam insulation ($1.00 to $1.50)

While the typical range in cost for having spray foam insulation professionally installed is $1,284 to $3,741, prices vary within that range based on the type of spray foam insulation.

The cost of labor to have spray foam insulation installed is a sizable portion of the final tally. Most spray foam insulation pros have to be trained to install the specific brand of insulation, and they use a spray rig designated by the manufacturer. The cost for the labor portion of the project ranges from about $50 to $100 per hour, depending on location. Labor doesn’t vary significantly by the type of insulation, so both open-cell and closed-cell applications will have similar labor costs.

The size of the area to be insulated plays a vital role in how much the project will cost. A small project with just 100 square feet of wall that needs insulating will run $44 to $150, on average, to have it insulated with spray foam. However, most projects are more extensive, and homes with 3,000 square feet of wall space would range from $1,320 to $4,500 to complete the project.

The cost to have spray foam insulation installed can also vary from location to location, depending on how many companies offer the service, the demand for the service, and average labor costs. For example, the average cost to have spray foam insulation varies widely in the following communities:

Don’t guess what the cost might be in your area; call at least three insulation contractors and ask for estimates to get a better idea.

The best time to install insulation of any type is during new home construction when the wall spaces are open and insulation is easier to install. At this point, the labor costs to install spray foam insulation, which range from around $50 to $100 per hour, are going to be less because the spaces are easily accessible to the installer.

However, in an existing home, portions of drywall may need to be removed to access the stud spaces, and specific installers may decline to tackle the job if the spaces are not visible. Spray foam insulation is designed to be applied in thin layers that expand up to 1 inch thick. Each layer should dry completely before subsequent layers are added. Having to remove drywall to access the stud and rafter spaces will add to the cost of insulating.

Moisture can damage some types of insulation, such as fiberglass batts that tend to compress when they get wet and lose their insulating value. Leaks inside wall cavities destroy fiberglass insulation, but they can lead to the growth of mold, which should be removed before the wall space is insulated again.

Mold remediation costs an average of $1,500 to $3,500, depending on the size of the area being treated and the going rate of labor in the community.

Some local building codes require installing a vapor barrier in exterior walls to keep moisture from passing through. If so, closed-cell spray foam insulation is suitable for use as a vapor barrier. However, open-cell insulation is not an acceptable vapor barrier, so if the homeowners want open-cell insulation, but a vapor barrier is required by code, an additional vapor barrier will be necessary and could run an average of $0.65 to $1 per square foot.

While the traditional and most common types of spray foam insulation are polyurethane-based, other types are available, and some are more eco-friendly. Choosing an alternative kind of spray foam is unlikely to affect the cost of installation, however, as most of the price variation when it comes to installing spray foam is dependent on the thickness of the product and the going cost of labor in different communities.

Most spray foam insulation on the market today is made from polyurethane, which offers good insulating value, but tends to off-gas for a few years. Off-gassing is the releasing of volatile organic compounds (VOCs) that may cause a noticeable chemical odor. Off-gassing is strongest in the first year after installation and should end entirely in 4 to 5 years. Expect to pay $0.44 to $1.50 per board foot for professional installation of polyurethane foam insulation.

Soybeans are grown for various food and non-food sources, and one of those uses is as a component of spray foam insulation. Soybean-based foam contains few or no VOCs, so there’s no objectionable chemical smell that some home residents may find troublesome.

Because soybeans can be planted and harvested on an ongoing basis, those looking for an eco-friendly alternative to polyurethane-based insulation may want to request a soybean-based product, as soybeans are considered a sustainable product. The total cost will be based on the size of the project; for example, insulating a 500-square-foot ceiling averages $220 to $750, while a more extensive 2,500-square-foot project could run as much as $3,750.

Water-based spray foam may also be an option for those looking for an alternative to polyurethane-based foam. Having it installed will cost approximately the same, ranging from $0.50 to $2.50 per square foot, depending on whether it’s open-cell or closed-cell insulation. The size of the project, as well as the going rate for labor, is also a consideration.

While some types of spray foam insulation are advertised as being made from vegetable oil, virtually all are still made from soybean oil, which has unique components that make it suitable for creating a long-lasting insulating product. The cost will be competitive with other types of foam, but soy- and vegetable-based foams may not be available in all locations.

Several areas of the home can benefit from the use of spray foam insulation. Since it sprays on as a liquid and then expands to fill gaps, it creates an airtight seal that can eliminate most sources of drafts, and it also dampens sound transfer between rooms. Good spots for spray foam insulation include:

Insulating a home helps conserve energy and helps maintain a comfortable indoor climate for residents. While a variety of insulation types are available, because spray foam also acts as a sealant, it’s up to 50 percent more efficient than some other types, such as fiberglass batts or cellulose fibers.

Drafty windows and other sources of air leaking in and out of a home can account for as much as 40 percent of a home’s energy cost. While all insulation will help increase a home’s thermal resistance, spray foam is the only type that will seal air leaks, resulting in lower utility costs. The initial cost of installing spray foam insulation in home ranges from $1,284 to $3,741, which is higher than installing batts, but if you live in an area where heating and cooling costs are high, it could pay for itself in a few short years.

Moisture and construction materials don’t mix—water that leaks through siding can damage a home’s wooden structure. Closed-cell spray foam insulation, which runs an average of $1,500 to $2,250 to insulate 1,500 board feet, is an effective sealant to keep out air, but it serves an extra purpose that open-cell foam does not. Closed-cell foam acts as a moisture barrier to help keep water away from building materials.

Spray foam insulation forms a dense layer between wall studs, giving it excellent soundproofing ability. Both closed- and open-cell spray foam insulation can be installed in wall cavities to reduce sound transfer. This can be beneficial when installed in exterior walls to help block the sound of a busy street and in common walls between separate living spaces in duplexes and apartment complexes. The national average for insulating an entire home with spray foam is $2,492.

The denseness and sealant qualities of spray foam insulation give it more thermal resistance than other types of insulation. R-value is measured by the material’s ability to reduce hot and cold thermal transfer by 1-inch thickness. Closed-cell foam insulation offers the highest R-value.

While homeowners will pay more for spray foam insulation over other standard types, the product not only seals out air better, but it also comes with a longer useful life—up to 80 years, which is up to three times longer than other types. Considering that fiberglass batts and cellulose fibers will lose their loft when wet, which reduces their R-values, spray foam insulation holds its value longer.

Spray foam insulation does not absorb moisture, making mold and mildew less likely to grow. Areas that are traditionally damp, such as basements and crawl spaces, can benefit from spray foam insulation. Insulating the interior walls of a typical 1,000-square-foot basement runs about $2,100 before labor, and insulating a standard crawl space could cost about $80 (materials only) before factoring in labor costs.

While you can’t construct a wall with spray foam insulation, the densest type of foam, closed-cell, can help give a wall increased racking strength, meaning the wall is less likely to shift out of alignment. By adhering to the inner surfaces of the studs and then curing to a hardened material, it offers added shear strength to a wall. This makes it well suited for bolstering metal buildings while providing thermal resistance at the same time. The cost to insulate a 30-foot by 50-foot metal building with closed-cell insulation ranges from $1,600 to $2,400.

Improving a home to increase its energy efficiency may come with a rebate or tax credit. Check with your local building authority to see if any rebate programs might apply. In addition, in some cases, if homeowners update to improve energy efficiency, they may be able to claim a tax credit on their annual income tax return.

Enthusiastic DIYers are always looking to save money by doing their own projects, but spray foam insulating is usually best left to the pros. Some insulation manufacturers will only sell their product to trained and certified technicians, so there’s no way for a DIYer to purchase it.

On the DIY front, spray foam insulation is available in a kit, but the verdict is still out on whether these types of kits are a good option. Installing spray foam insulation can be a tricky process because it has to be applied in thin layers. If too much is applied at once, it can sag or swell beyond the surface of the wall studs. In this case, the excess must be cut away later.

Correctly installing spray foam insulation requires a skilled touch, and the product’s manufacturer will not likely warranty the installation if it’s not applied by one of their approved technicians.

Installing spray foam insulation in a new construction will cost less than installing it in an existing home because it can be sprayed in the wall and rafter spaces while they’re open. In a remodeling project, the installer may need to remove some wallboard or drill holes and use an injection method of installing the foam. Homeowners may be able to save a bit using the following tips.

Most homeowners will pay from $1,284 to $3,741 to have a home insulated. Much of that cost variation comes from the going cost of labor in a community and the difference in price between open-cell and closed-cell insulation. To get the best bang for the buck, consider asking the insulation contractor a few questions.

With the skyrocketing cost of heating and cooling a house, homeowners are always looking for ways to conserve energy and save money. While having spray foam insulation installed is more expensive than other types of insulation—running an average of $2,492 nationally—the extra expense can often be recouped in energy savings in a few years. For those considering spray foam insulation, a few questions are to be expected.

It’s probably not a good idea. Many manufacturers will sell their products only to trained and certified technicians, and using the product requires a good amount of skill.

The interior of a metal building will benefit from a 1-inch layer of closed-cell spray insulation foam, which will cost between $1,600 to $2,400 to have professionally installed.

Closed-cell spray foam insulation has the highest thermal resistance value, averaging R-6 to R-7 per inch. Open-cell foam averages R-3.5 to R-3.6 per inch.

Sources: HomeAdvisor, HomeGuide, Fixr, Thumbtack

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