R-value of Materials and DepthsMaterialR-value/in10″Cellulose blown (attic)3.2 – 3.732.0 – 37.0Cellulose blown (wall)3.8 – 3.938.0 – 39.0Polystrene Board3.8 – 5.038.0 – 50.0

What R-value is cellulose in walls?

Cellulose is an alternative to blown-in fiberglass. It’s a fiber made from around 80 to 85 percent recycled paper. Cellulose is denser than blown-in fiberglass, so it has a better R-value — about 3.2 to 3.8 per inch, however, it does settle and flatten over time, losing some of that insulating value.

Does cellulose insulation lose R-value when compressed?

Yes. Cellulose insulation does lose its R-value when it is compressed. The amount of loss depends on how much insulation is decompressed but typically ranges anywhere from 15% to 20% of its initial value.

What is R-value for cellulose in attic insulation?

Cellulose InsulationLoose Fill Fiberglass #2R-value3.8 per inch2.7 per inchDesign Density25.6 kg/m38.0 kg/m3

How many inches of blown cellulose insulation is R38?

R-ValueMin ThicknessMax Net Coverage / BagR4915”13.3R4413.4”15.1R3811.6”18R309.3”23.4

What is the best R-value for insulation?

Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces. See the Department of Energy’s (DOE) ranges for recommended levels of insulation below.

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.

How long does cellulose insulation last?

Because it is made primarily of recycled materials, however, cellulose insulation does degrade over time. The typical lifespan is 20 to 30 years, with degradation beginning as early as 15 years after installation. As with other types of insulation, severe weather or outside interference can reduce the lifespan.

Does blown in cellulose insulation settle?

Cellulose insulation, unfortunately, is most likely to settle. Over time, the aeration in cellulose insulation will decrease. This settling will cause cellulose insulation to lose up to 20 percent of its R-value. … By blowing in about 20 percent more insulation, you can account for settling.

Is it bad to compress blown in insulation?

Here’s what they say: 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. … So, you don’t get the full R-value on the label, but the insulation still works perfectly well if all you’ve done is compress it.

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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 R-value of 14 inches of blown insulation?

Warm Climates (R-30 to R-49): Fiberglass (blown): 14” – 18” Fiberglass (batts): 11” – 14” Cellulose (blown): 11” – 13”

How much cellulose insulation do I need for attic?

According to the U.S. Department of Energy, it’s recommended that attics have an R-38 to R-49, or about 12” to 15” of fiberglass or cellulose insulation.

Which is better blown-in fiberglass or cellulose?

At 3.5 per inch of material, the R-value of blown-in cellulose is 23% better per inch than fiberglass batts! According to research done at the Oak Ridge National Lab, fiberglass loses up to 50% of its R-value in very cold conditions; making cellulose a better choice for homes in northern climates.

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.

Is blown insulation better than batt?

In short, there is less chance of error with blown insulation as compared to batts. … Finally, while blown insulation is much more consistent and has a much lower chance of failure, the R-value of this insulation will typically have a higher R-value due to installation quality differences.

What is the thinnest insulation with the highest R-value?

Aerogel insulation offers the highest R-value of any insulating material at less weight and thickness—ideal for construction, refineries, pipelines, and thin-gap thermal barriers.

What is the R-value of blown in insulation in a 2x4 wall?

Fiberglass vats are the standard insulator for 2-inch by 4-inch wall framing, and are rated R-11 through R-15. In order to achieve the higher insulation R-value of R-21 a different type of insulation will be required.

What is the highest R-value for a 2x4 wall?

They are available in widths suited to standard spacings of wall studs and attic or floor joists: 2×4 walls can hold R-13 or R-15 batts; 2×6 walls can have R-19 or R-21 products.

Which insulation is best for attic?

Many people consider fiberglass batt to be the best attic insulation. It consists of plastic reinforced by small glass fibers. The batt version comes in blanket form — i.e., small, pre-cut sections that you can lay down wherever you need to.

What is the average cost of blown-in insulation?

The average cost of insulating with blown-in fiberglass is $0.50 to $1.10 per square foot, making it the most affordable choice. Achieving the necessary R-value is also a factor. Installing blown-in fiberglass to R-30 costs about $500 for a 1,000-square-foot attic. To reach R-60, it runs an average of $1,060.

How much does blown-in insulation compress?

Blown-in insulation made from rock wool or fiberglass typically loses between 2 and 4 percent of its insulating capacity due to settling.

Do mice like cellulose insulation?

The insulation has a low toxicity to mammals such as mice that filter out the poison through their livers, Ansley says. But because the cellulose insulation is loose and falls in on itself, rodents don’t like it and will often leave because they prefer areas where they can burrow in order to nest.

Do I need a vapor barrier with cellulose insulation?

With Modern’s Cellulose insulation, a vapor barrier is not recommended except in very cold weather or high moisture areas such as spas or pool buildings. However, many building codes do require an Air barrier or Vapor retarder to be installed. … Cellulose insulation has a high density compared to fiberglass.

What is the highest R-value for a 2x6 wall?

Thermal Control The installed insulation R-value for 2×6 fiberglass batt ranges between R-19 and R-21. When blown or sprayed cellulose insulation is used, the R-value is typically R-20 for 2×6 walls.

Does squashing insulation stop it working?

Increases heat loss – the money you spent to improve the energy efficiency of your home will be wasted if you install standard boarded – squashing insulation stops it from working. Some installers will even remove installation to make way for boarding.

Can you double up on insulation?

Doubling the thickness of insulation will double the insulation’s R-value, cutting heat loss in half. Each time the insulation layer is doubled in thickness, this rule applies. … In some cases, like an attic, it’s worth piling on more insulation because there is plenty of room.

Is R30 insulation good for attic?

R30 insulation is the minimum insulation recommended for an Attic from climate zone 1 to 3, while it can be used in cathedral ceilings in all climate zones across the USA. It can be used as maximum insulation in climate zones 4 – 8 of the USA for floors.

What is the R-value of closed cell foam?

The R-value of closed-cell foam is R-6.5-7 per inch. Contractors often use it to insulate under slabs, ceilings, walls, and roofs.

How many bags of insulation do I need in my attic?

Loose Fill Attics: R-30, 10.5” deep, (33lb./bg) = 13 bags. Dense pack walls: R-13, 2” x 4” wall, (33lb./bg) = 13 bags. Dense pack walls: R-21, 2” x 6” walls, (33lb./bg) = 21 bags.

How thick should blown 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).