Calculating Spray Foam Insulation Cost

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Spray foam insulation is one of the best insulation materials available on the market. Made for high tech polyurethane foam, it is installed by spraying two liquid components into an open cavity, like in between the studs of an unfinished wall, or into the roof deck of a home.

This extremely durable material also provided the added benefit of its hydrophobic properties, meaning it repels water. It comes along with a high R-value of 7 per inch, making an extremely efficient insulator.

The cost of the initial installation can be a little bit higher than other traditional materials, but the insulating value of spray foam, as well as the myriad other benefits that come along with it, will outweigh those costs in little time.

When calculating the spray foam insulation cost, there are several factors you will need to consider.

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Open Vs. Closed Cell

Spray foam comes in two varieties, open and closed cell foam. Open cell is less pricey, and can be good for use in certain applications, closed cell is far more effective, and comes with more secondary benefits.

If you are going to shell out the money to have spray foam professionally installed, you will probably want to use closed cell foam, ensuring you get the most bang for your buck.


You’ll need to know how thick you want to spray your foam. In most climates, 1 inch of foam may not provide enough insulation power. You are likely going to have to add more. Most home builders recommend at least 2, but you are probably going to want more like 3-4 inches.

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The depth of foam you are able to add is also going to depend on where you are installing it, and how much space you have to work with.

Square Footage

The size of the area you intend to insulate is going to be the biggest factor when it comes to determining the cost of your insulation project.

You can get a general estimate by using this formula: (square footage)x(R-value)=total cost.

Alternatively, the average price of installing spray foam is between $0.44 and $1.50 per board foot. That means 1 square foot area that is covered in one inch of foam. So, determine the total square feet of your project, multiply by the depth you want the foam, and voila – you have your estimate. That’s assuming we are using $1 as the price per board foot (which is about the midpoint of the high and low average price).

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Contractor Experience

The last factor that will come into play when determining the cost of your spray foam insulation project is who you choose to install it. Contractor estimates can vary greatly, and that is partly because of the difference in experience they have, and the quality of work they are able to deliver.

You may be tempted to choose a contractor who gives you a lower estimate, however this could end up costing you big time in the long run. If the job is done poorly, you may end up having to redo it down the line, or you could be missing out on energy savings.

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The cost of installing spray foam insulation can be a deterrent for many homeowners. However, this is investment that will pay for itself by reducing your monthly utility bill, and will last for the lifetime of your home.