Spray Foam R Value

Spray Foam R Value

What is R-Value?

When it comes to insulating your home, R-value matters. Without getting too technical, insulation effectiveness is measured in R-value.

The higher the R-value, the more effective the insulation in preventing heat transfer.

The bottom line is that spray polyurethane foam is better than any other type of insulation for reducing air leakage. According to greenbuildingadvisor.com, closed-cell spray foam provides an R-value per inch of 6.5, compared to other insulation types such as cellulose and fiberglass, with R-values of only about 3.5 to 3.7, making it the “king” of insulations.

How long does spray foam R-value last?

Some may question whether spray polyurethane foam R-value diminishes over time. Many industry studies suggest that the answer is brief, yes… followed by a comforting and long-lasting no.

When first installed, the R-value of closed-cell spray polyurethane foam is actually about 10 for a one-inch thickness.

Overtime (around six months typically), it will drop to 6.5, then stabilize and retain its still-way-higher-than-all-other-insulations value of 6.5 for decades. Industry experts suggest that other types of insulation, especially those that can absorb moisture and “mat down” can suffer huge and permanent (up to 50%) R-value loss over time.

Is closed cell spray foam the only way to go?

R-value measures an insulation's ability to resist heat flow.

Of course, closed-cell may not be the best choice for Louisiana attic insulation, since it would make detection of leaks impossible should they occur. In such cases, open-cell spray foam, with a density of .05 per square inch, would be a better choice.

Sunlight typically recommends 5.5″-7.5″ depending on the application. Both closed and spray polyurethane foam insulate and act as an air barrier keeping your home comfortable and reducing heating and cooling costs for the life of your home.

Another insulation value to consider…

But remember, in addition to R-value, you should also consider a little something that you could call “C-value” — AKA the value of your contractor! As with any type of insulation, the product is only as good as its installer. Sunlight Contractors have a proven reputation for consistently excellent professional results – with hundreds of five-star reviews.


No other energy solutions provider can offer the savings and services that Sunlight Contractor does. From evaluations and estimates to energy conservation and production, we’re your one-stop-shop for energy efficiency with fair spray foam insulation costs.

Call or email Sunlight Contractors today to learn more about which products will work best for your specific situation. Sunlight Contractors not only offers products with the best R-value — but you always get the best “C-value” too!

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