Blown fiberglass installed in the attic has an R-value of 2.2 per inch, so 12 inches of it would give you an R-value of 26.4 in your attic installation project.
What is the R-value of 1 inch of fiberglass?
R value measures the resistance of heat transfer from one side of an object to another. For example, one inch of solid wood has an R value of 1. In comparison, an inch of blown fiberglass insulation has an R value of 3.1 – 3.4, and an inch of closed cell spray foam insulation has an R value of 6.
What R-value is 6 inches of insulation?
Fiberglass Insulation Batts
Fiberglass blankets or rolls provide an R-value of up to 3.2 per inch, so a 6-inch fiberglass batt may achieve an R-value of 19.2, and some high-performance products are rated at R-21.
What is the depth of R-38 blown insulation?
To attain an R-value of R38, a depth or thickness of the blown-in insulation of 15,7″ is needed for fiberglass and 11,98″ for cellulose. Cellulose is seen as a more sustainable means of insulation, with the recycled paper being used as insulation.
What is the highest R-value for fiberglass insulation?
Fiberglass batts and rolls are ideal for placement between framing during construction in floors, walls, attics, and ceilings. They’re denser than blown-in insulation, offering an R-value of up to 4.3 per inch.
Can you put too much insulation in your attic?
It’s possible to over-insulate an attic as too much will cause moisture buildup and eventually result in mold. Eventually, adding more insulation leads to diminishing returns in trapping heat as well.
What is the R-value of 2 inch fiberglass insulation?
Here are the R-values per inch of the most common types of insulation: Fiberglass (blown): 2.2 – 2.9. Fiberglass (batts): 2.9 – 3.8. Cellulose (blown): 3.1 – 3.8.
How thick should blown in insulation be?
When blown into attics and wall spaces, loose-fill fiberglass offers an average R-2.5 thermal value per inch (the higher the number, the greater the insulating effect). You’d need a thickness of about 7.5 inches of insulation to match the insulating value of a batt of R-19 insulation (R-19 is a common batt value).
How thick is R30 insulation?
Typical R-30 fiberglass insulation is 10-inches-thick. Prior to buying fiberglass insulation, it is important to measure the joint spacing you are working with. Note that the actual space between the framing members will be less than 16 or 24 inches, but the foam batts can easily be stuffed between these lengths.
Does fiberglass have a high R-value?
Fiberglass insulation does not have the highest R-value on the market, but it is one of the most cost-conscious options. The R-value for fiberglass batts ranges from 3.1–3.4 per inch of thickness. For loose-fill fiberglass insulation in an attic, the R-value is 2.2–4.3 per inch and for the wall is 3.7—4.3 per inch.
What is the R-value of 3.5 inches of spray foam?
Open-cell spray foam absorbs and holds water. It has a lower R-value per inch than closed-cell foam and is vapor-permeable. The R-value is R-3.5 to R-3.6 per inch, so filling a 2×4 cavity yields about an R-13.
How many inches of blown insulation should be in my attic?
The higher the R-Value, the better the thermal performance of the insulation. The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.
Does fiberglass insulation lose R-value when compressed?
When you compress fiber glass batt insulation, the R-value per inch goes up, but the overall R-value goes down because you have less inches or thickness of insulation.
What is the R-value of 2 inch Styrofoam?
A wall utilizing STYROFOAM T-MASS Technology with a 2-inch exterior layer and a 4-inch interior layer of concrete along with a 2-inch layer of STYROFOAM extruded polystyrene insulation would result in a material R-value of approximately 11.33.
What R-value is spray foam?
The R-Value for spray foam insulation can vary depending on the product, manufacturer, and other variables. Open cell spray foam insulation is R-3.6 to R-3.9 per inch. This R-Value is normal for open cell spray foam. Closed cell spray foam insulation is R-6 to R-7 per inch.