Improving the insulation in your home is one of the most important steps you can take to make your house more energy efficient. While there are various types of insulation that can be used, foam insulation is durable, economical and offers superior R-value.
On average it costs $2.50 to $5.25 per square foot to install spray foam insulation, including labor and materials. For a 1,000 sq.ft. space, applying spray foam insulation costs $1,500-4,000, depending on the type of foam you use, accessibility and local labor rates.
Without proper insulation, the house never seems warm enough and the air conditioning doesn’t keep all of your rooms cool.
You may even decide that the heating and air conditioning equipment need to be replaced when the real problem is insufficient insulation. Insulation is also a barrier to moisture, allergens and noise.
Find out how much spray foam insulation costs, its pros and cons, how it compares to fiberglass and blown in cellulose insulation, as well as spray foam’s energy efficiency (R-value).
What Is Foam Insulation?
There are many different types of insulation. The most commonly used are fiberglass, foam and blown in cellulose.
Natural fibers such as cotton and wool are also used, along with mineral wool (made from rock or slag) and denim. These can be applied as loose fill; in cut sections called batts; rolls; foam boards and spray.
Foam insulation, also known as spray foam insulation is a plastic-like material made when two, separately stored liquid chemicals are mixed and sprayed on-site. The liquids expand very quickly on contact to create a dried foam of bubble-like cells. This foam insulates, seals gaps and can form air, moisture and vapor barriers. It is used most often to insulate
– attics
– basements
– crawlspaces
– wall cavities
You may have used a can of spray foam around the foundation of your home to seal small gaps and cracks, often around where pipes or wires enter your home. This relatively easy, DIY project helps keep insects and moisture out of your home.
When it comes to sealing the larger spaces between the joists in your attic, walls and basement, spray foam insulation should be done by a professional.
How Much Does Foam Insulation Cost?
Open-cell spray foam costs typically $0.25 to $0.50 per board foot and closed-cell spray foam ranges from $0.90 to $1.50 per board foot. A board foot is a measurement of volume (length, width and thickness).
The cost depends on the parts of your home you want to insulate and to what thickness. You should get several estimates, which are usually free. Prices may be lower in late Fall and Winter when contractors are not as busy.
Purchasing a new home with spray foam insulation or retrofitting your existing home may qualify you for tax credits, rebates, and other incentives. To find available local and state incentives, visit the Database of State Incentives for Renewables & Efficiency (DSIRE) at http://www.dsireusa.org/.
Cost of spray foam insulation vs other insulation types
This chart shows the cost comparison per square foot between spray foam and other types of insulation. Note, that the listed prices are for the cost of insulation itself, and does not include the cost of labor.
| FIBERGLASS | BLOWN IN | SPRAY FOAM | MINERAL WOOL | |
|---|---|---|---|---|
| MATERIAL & INSTALLATION COST ONLY | $0.64 - $1.19 per square foot $640 - $1,190 for 1,000 square feet | $1.00 - $1.33 per square foot $1,000 - $1,330 for 1,000 square feet | Open Cell: $0.35 - $0.55 per board foot $350 - $550 for 1,000 board feet Closed Cell: $1.00 - $2.00 per board foot $1,000 - $2,000 for 1,000 board feet Note: Spray Foam insulation is measured by board foot which is a measure of volume (length, width, thickness) | $1.03 - $1.90 per square foot $1,030 - $1,900 for 1,000 square feet |
Foam Insulation Costs Room by Room
Here is a chart with estimated costs for spray foam insulation in various rooms/remodeling projects around the house.
| MATERIAL & INSTALLATION COSTS (Not incl. cost to open walls, ceilings or floors, if need) | UNFINISHED ATTIC Floor/Walls 1,000 sq. ft. coverage area | UNFINISHED ATTIC Roof Rafters 1,000 sq. ft. coverage area | BASEMENT 1,000 sq. ft. | BEDROOM 288 sq. ft | FAMILY ROOM ADDITION 430 sq. ft. |
|---|---|---|---|---|---|
| FIBERGLASS $0.64 - $1.19 per square foot | $640 - $1,190 | $640 - $1,190 | $640 - $1,190 | $184 - $343 | $275 - $512 |
| BLOWN IN $1.00 - $1.33 per square foot | $1,000 - $1,330 | N/A | N/A | $288 - $383 | $430 - $515 |
| SPRAY FOAM CLOSED CELL $1.00 - $2.00 per board foot | $1,000 - $2,000 | $1,000 - $2,000 | $1,000 - $2,000 | $288 - $576 | $430 - $860 |
| SPRAY FOAM OPEN CELL $0.35 - $0.55 per board foot | $350 - $550 | $350 - $550 | N/A | $100 - $158 | $150 - $237 |
| MINERAL WOOL $1.03 - $1.90 per square foot | $1,030 - $1,900 | $1,030 - $1,900 | N/A | $297 - $547 | $443 - $817 |
Two Types of Spray Foam Insulation
There are two types of spray foam insulation: closed cell, which comes in high and medium densities and low-density, open cell. Each one is best suited to specific uses.
Closed Cell Spray Foam
In closed cell spray foam insulation, the cells are filled with a gas and tightly compressed preventing air and moisture from getting through the foam.
Closed cell insulation expands to about 1” of thickness when sprayed. It is the best choice for insulating where space is an issue. The rigid nature of closed cell foam also adds to the structural integrity of a building.
There are versions of this product which also lower the potential spread of fire and minimize the resulting production of smoke.
Close cell foam may not require an additional vapor retarder such as sheetrock or plastic sheeting stapled on interior walls because it is less vapor permeable than open cell foam. By controlling moisture, spray foam can limit one of the variables that can lead to the growth of mold and mildew. This makes it a good choice for basements.
If you live near a creek or other flood prone areas, or if you have an older home with poor basement drainage, paying for closed cell foam may be worth the potential cost of damage to your home.
Closed cell insulation has an R-Value of around 6.9 per inch which open cell has an R-Value of about 3.9 per inch. R-Value is a measurement used to determine how effective an insulator is in resisting air flow.
The disadvantage of closed cell foam is that it is denser and requires more material to fill a space, making it more expensive to use. A professional will know where to use closed cell spray foam in the most cost-effective way.
Open Cell Spray Foam
In open cell foam the cells are not enclosed so air is able to fill the spaces making it lighter and more flexible. The open cell spray foam expands quickly to a 3” thickness and can be trimmed if it overfills a space.
The complete and rapid filling of this insulation seals everything completely. Its thickness and complete coverage also make it excellent for soundproofing.
Open cell spray foam is less expensive than closed cell. Its thick layer makes it a better choice for insulating certain spaces because it can fill the space in one application making it more cost-effective to use.
In areas of high humidity open cell insulation will usually require a vapor retarder. If open cell foam gets wet from a leak it will dry out and return to normal once the leak has been stopped. However, in the case of a flood that lasts for days where the foam is submerged, the pressure and weight against the foam will likely damage the open cell structure beyond repair.
It costs 25% less then closed cell insulation.
On the downside, here are some factors you should consider before installing open cell spray foam:
– Offers about half the R-value compared to closed cell insulation (maybe even 2/3)
– It is more water permeable than closed cell insulation. For example, if you have a roof leak or a bad wall leak, open cell foam insulation may absorb up to 35% of water by volume after 96 hours. Eventually, open cell foam will absorb enough water to cause major problems, such as rotting the wood, very bad odor, mold problems, etc.
High, Medium vs Low Density Foam Insulation
High density closed spray foam is chosen by builders to add structural strength and high insulation values in new construction. It is often used for roofing or other exterior insulation because it is seamless and impenetrable.
The bond that spray foam forms to the roof can increase a building’s resistance to wind uplift. Wind uplift is the push-pull force of air pressure and wind around the roof. This can reduce the damage experienced during periods of high wind.
It can also help reduce energy costs significantly over a roof’s lifetime because it slows heat loss and increases protection against air and water infiltration.
Medium density spray foam is often used for continuous insulation across interior wall cavities and for unvented attic applications. Medium density spray foam is a closed cell foam used where there is a need for the greatest R-Value per inch in the space available. It acts as an air, vapor and water barrier and can even help reduce noise.
Low density, open cell foam also provides continuous insulation. It can be applied on walls, in unvented attics, to ducts and ceilings, and in vented attics and crawl spaces. It is known as an air barrier, but is permeable to vapor and moisture.
Due to its relatively large cell structure, low-density foam stays somewhat soft and flexible after curing. It provides heat insulation and prevents airflow from entering through cracks, joints and seams by filling the spaces completely. The softer texture and open cell structure mean it can also help absorb sound.
Which Type Of Spray Foam To Use?
The choice of which spray foam to use depends on many of the factors discussed above. Some foam is inappropriate in specific applications. For example, you typically would not use open-cell foam below grade (ground level) or in places where it could absorb water.
The most common reason to choose closed cell over open cell is that it combines vapor, air and thermal barriers all in one. It also provides the highest R-value in the smallest space.
This is very important places like in New England where most homes have 2×4 walls and 2×6 roof rafters. Open cell foam may overfill those spaces and need to be trimmed. Your experienced insulation professional will be able to advise you as to the best type to use for each particular area of your house.
Installation Considerations
Open cell insulation is applied in a single spray application and then it expands the entire depth of the wall cavity. The excess is then trimmed off with a special cutter. So if you have tight access to a particular part of the building envelope, its good to use open cell insulation as it has a much higher expansion rate and will completely fill that cavity.
On the other hand, closed cell insulation is applied in multiple layers. For each layer, the depth should not be more than a 2 inch average. Otherwise, there is a good chance you will have a very bad smell problem.
Also, closed cell insulation does not expand as much as open cell foam. This make it not the best choice for small spaces with limited access, where you cannot reach far enough. This may result in air gaps left in the cavity.
Pro Tip: Open cell has about 3 times the expansion rate of closed cell insulation.
Benefits of Spray Foam Insulation
-Helps lower energy bills by up to 20% according the Energy Star
-Increases the structural integrity of your home.
-Lowers maintenance costs which lead to reduced roof repairs
-Makes your home more comfortable by decreasing drafts and keeping all the rooms at the same temperature
-Improve air quality by preventing moisture and allergens from entering the house
-Makes your house more energy efficient thereby allowing you to install smaller heating and air conditioning equipment during new construction
-Conforms to the design and shape of all homes including those with complicated structures, hard-to-reach places and domed ceilings.
-With spray foam, builders can lower construction and remodeling costs, meet or exceed stringent building codes and reduce the need for additional sealant materials. It also can help builders meet the energy efficiency requirement of programs such as Energy Star, LEED and NAHB Green Building
-Energy Star Certified Insulation. When an insulation product is Energy Star certified it means it has been certified by EPA (Environmental Protection Agency) recognized third-party certification organizations.
-It is independently tested to ensure that it delivers performance while meeting strict safety standards. Energy Star also requires that certified insulation is tested to meet flame resistance requirements.
Can You Install Spray Foam Insulation Yourself?
Open-cell spray foam typically uses water or carbon dioxide as the blowing agent that allows the foam to spray. This is less harmful to the Earth’s climate than the HCFC (hydrochlorofluorocarbons) blowing agents which are being gradually phased out but are still being in closed cell spray foam.
When talking with an insulation contractor who recommends closed cell foam request a brand that does not use HCFC.
The chemicals which are used for spray foam insulation are very powerful irritants to the eyes, lungs, skin and gastrointestinal systems.
If they are not mixed properly the chemicals don’t fully react and can remain in a toxic state inside your walls. In a very small number of cases, incorrect application of spray foam has sometimes resulted in ongoing fumes and smells for the homeowner, when the foam failed to cure properly.
Improper spray foam installation can also generate enough heat to cause a fire. The chemical reaction that occurs during spray foam installation generates heat. If foam is applied too thickly or if layers of foam are applied on top of one another too soon, the foam may char, smolder or burn.
Spray foam insulation must be mixed and installed correctly at your home, by a trained technician.
The exception is for small spray foam jobs to fill small cracks around sills, window openings, etc., that you may choose to do carefully yourself with spray foam cans available at hardware stores.
Check for references from customers when you are choosing a spray foam insulation company. Also be aware that you should stay away from your home during spraying and for about two days after while the foam cures.
There are so many areas of maintenance involved with owning a home. Some people try to do DIY projects whenever possible. They enjoy the accomplishment of learning something new, of improving their home and potentially saving money.
It’s important to know which projects are better left to a professional. Spray foam insulation is one of those projects because of the depth of knowledge required and the intricacy of the materials to get it right.
Foam Insulation vs Other Types Of Insulation
Here is a chart that compares different types of Energy Star Insulation to foam insulation.
| BLANKET: BATTS AND ROLLS | LOOSE FILL AND BLOWN IN | SPRAY FOAM | FOAM BOARD OR RIGID BOARD | RIGID FIBEROUS OR FIBER INSULATION | |
|---|---|---|---|---|---|
| MATERIALS: | • Fiberglass • Mineral Wool (rock, stone or slag) • Plastic Fibers • Natural Fibers (cotton, wool) | • Cellulose • Fiberglass • Mineral wool (rock, stone or slag) | • Cementitious • Phenolic • Polyisocyanurate • Polyurethane | • Polystyrene • Polyisocyanurate • Polyurethane | • Fiberglass • Mineral Wool (rock, stone or slag) |
| BEST SUITED FOR: | • Unfinished walls, including foundation, basement and crawlspace walls • Floors and ceilings | • Enclosed existing wall or open new wall cavities • Unfinished attic floors • Other hard-to-reach places | • Enclosed existing wall • Open new wall cavities • Unfinished attic floors, attic ceilings | • Unfinished walls, including foundation, basement and crawlspace walls • Floors and ceilings • Unvented low-slope roofs • Exterior continuous insulation • Exterior below grade foundation walls | • Ducts in unconditioned spaces • Other places requiring insulation that can withstand high temperatures |
Is Spray Foam Insulation Worth It?
The cost of insulation depends of several factors including:
Labor
Quantity of material required
Type of insulation required
Project location
Building code requirements
Project size
The initial investment of spray foam insulation is well within the same range of the cost of other types of insulation. In addition, there are cost savings opportunities both in new construction use of spray foam insulation and in retrofitting existing homes.
These include Energy Star cost savings, rebates, smaller sized heating and air conditioning equipment, fewer roof repairs and more comfortable living.
The typical lifespan for fiberglass batt insulation is 15-20 and 20-30 years for blown in Insulation. Spray foam insulation is one of the most durable and effective forms of insulation. It typically stays put until it is physically removed.
Insulation is one of those things that doesn’t necessary draw peoples attention when they are looking for houses, but it sure is important to them once they move in and start getting utility bills. Good article.