Whenever someone thinks of insulating their house, the best option that tops the list is spray foam insulation. Spray foam insulation is the best form of insulation that protects your house and has many added benefits attached to it. The versatility of the insulation makes it useful in diverse places like the attics, walls, basement, and many such places.
If you want to install spray foam insulation then knowing the R-value of the insulation will be very helpful to make your final decision.
With this article, we try to answer this question. You will learn about the R-values of the different types of foam insulation, it will help you to better understand which type of spray foam insulation is best suitable for you. It will help you make a better decision.
What is the R-Value of spray foam Insulation?
If you go about finding the R-value of the traditional insulation, it will be very easy but finding out the R-value of spray foam insulation will be a bit tough. To ease up your work, we have compiled this article to give you all information right here on this website. Read on to know further.
The R-value of insulation material is the thermal resistance of the material. It is the resistance to the heat flow that the material offers to external factors.
The thermal performance of a material is dependent on the R-value of the material. The more the R-value of a product, the more it will resist the flow of heat from the material, that is higher R-value is an indication of the higher insinuating capacity of the material.
Here is a table of the R-values of open and closed cell spray foam insulation along with their minimum and maximum depths.
R-value Per Inch
Minimum Thickness R-Value
Maximum Thickness R-Value
Here is a brief description of the R-values of the different types of spray foam insulation:
R-value of open-cell spray foam insulation
In this type of spray foam insulation, the cells are sparsely placed. It leads to a lower density for the open-cell spray foam insulation. The sparse placement gives the insulation a lower density as compared to the closed-cell insulation. It also gives the open cell insulation a spongy texture.
Even though it does not have an impressive R-value like closed-cell insulation, it still can be used for insulating. It is a bit cheaper than closed insulation, so if you are tight on your budget then you may want to opt for this type of insulation.
The open-cell spray foam R-value is 3.8 per inch. It is equivalent to fiberglass and cellulose. But you can surely use it for insulating your household.
R-value of closed-cell spray foam insulation
In closed-cell spray foam insulation, the cells are tightly packed together. They are placed very tightly next to each other. Due to this placement, this type of insulation has the highest density.
Due to its high density, it offers the least space for heat to escape. It implies that this type of insulation has a high R-value. Indeed it has the highest R-value compared to the insulations available in the market.
The closed-cell spray foam R-value is between 6.5 – and 7 per inch if installed correctly.
The higher R-value per inch makes it the best option for wall insulation and insulating other spaces. Therefore it has been widely used today.
What is the R-value of 2-inch spray foam?
For open spray foam insulation, the R-value is between R-7 and R-8. For closed spray foam insulation, the R-value is between R-13 and R-14.
If you want to go for open-cell insulation then it will be softer and spongier as compared to the closed-cell type of insulation. The closed spray foam insulation will be a lot tough in the two-inch format.
It will be better to speak to a professional for knowing whether this insulation will be suitable for you or not.
What is the R-value of 4-inch spray foam?
For open spray insulation in the 4 inches thickness, the R-value is 15.2. For closed spray foam insulation in the 4 inches thickness, the R-value thickness is 28.
What is the R-value of 6 inches of spray foam?
For the open cell insulation in the 6 inches format, the R-value is 22.8. For the open cell insulation in the 6 inches format, the R-value is up to 42.
Does spray foam lose R-value over time?
The simple answer is no! The spray foam insulation does not lose its R-value over time. It is sturdy and lasts for a long time without any degradation in its R-value. It is one of the most effective forms of insulation available on the market.
Unlike its competitors available in the market which tend to lose their R-values and effectiveness with time, spray foam insulation is very effective and long-lasting.
R-values of other insulating materials compared to spray foam insulation
When you compare the R-values of the other insulating materials available in the market with that of the spray foam insulation, you will find that the R-value of spray foam insulation is higher. The spray foam insulation has an air seal that prevents any air leak or heat transfer through the air.
The other insulating materials like fiberglass and cellulose do not have air sealers, which leads to heat transfer through them with the help of air movement. Whereas the spray foam insulation has air sealers that help the insulation prevent any kind of heat transfer.
So obviously in the materials like fiberglass and cellulose, the R-value will be much lower as compared to the spray foam insulation.
So we know that the spray foam insulation R-value is higher as compared to other insulators.
The Bottom Line
Spray foam insulation is an effective form of insulation. It has got a versatile nature because of which it can be applied to various spaces including your attics, wardrobes, basement, and walls. It has a high R-value and lasts longer than almost all other types of insulation material.
If you have a tight budget then you can go for open-cell spray foam insulation. Both types of insulation come with high R-values and a great lifespan. The closed-cell type spray foam insulation has a higher R-value than the open-cell insulation. You can use it for soundproofing and moisture protection.
Open-cell insulation can be used for soundproofing, as it expands more than the closed type, filling every nook and corner of your space. Also, it is cheaper than the closed-type.
Closed-cell insulation comes with a vapor barrier whereas open cell insulation does not have a vapor barrier. Also spray foam will help the walls of your house to become sturdy and strong.