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

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.

Is blown-in cellulose insulation good?

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 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.

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 12 inches of blown insulation?

The number is presented per inch, so an R-value of 3.1 at 12 inches would provide an overall value of R-38.

How long does blown-in 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.

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”

Is cellulose insulation more expensive than fiberglass?

When comparing blown-in insulation, both fiberglass and cellulose are nearly identical in price, both costing around $0.70 to $0.80 per square foot for 6 inches of insulation. Fiberglass batts, however, are less expensive, costing on average $0.30 to $0.40 a square foot for 6 inches of insulation.

Article first time published on

Which cellulose insulation is best?

The best manufacturers of cellulose insulation include GreenFiber, Insulmax, Applegate, and Nu-Wool. RetroFoam of Michigan has more than 17 years of experience specializing in injection and spray foam insulations. While we specialize in foam, we have dealt with cellulose in homes that needed new or updated insulation.

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.

How many inches of blown-in cellulose insulation do I need?

With blown-in cellulose insulation, that would require insulation to a depth of 10 inches. If there is already insulation, measure the current depth and subtract to determine the amount needed to bring the attic to the recommended level for the desired R-Value.

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

Fiberglass and rock wool batts—2×4 walls can hold R-13 or R-15 batts; 2×6 walls can have R-19 or R-21 products.

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

Cavity insulation, like framing, has options. A 2×4 wall cavity can be insulated from R-13 to roughly R-25. A 2×6 wall can be insulated from R-19 to R-39.

What is the R-value of pink batts?

The Pink® Batts® insulation 140mm wall range has higher R-values that go up to R4. 3 and can achieve a higher thermal performance than when the thickness is restricted to 90mm where R2. 8 is the highest R-value achieved.

What insulation has the highest R-value per inch?

Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch.

Can you put cellulose insulation over fiberglass?

No. Even if you have moisture in your attic, once all bypasses are sealed (and/or your roof repaired by a qualified contractor, if necessary) cellulose is blown directly over the existing insulation. … Adding new cellulose insulation on top of existing fiberglass insulation is called “capping”.

How much cellulose do I need?

To determine how much cellulose insulation you need, take the square footage of the space and divide it by either the depth or the desired R-value. Fiberglass blow-in insulation is essentially made up of spun fibers from recycled molten glass.

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.

How thick should cellulose insulation be in attic?

For loose-fill cellulose, this translates to a total depth ranging from 8 inches up to 16 inches. Fortunately, attic insulation can be upgraded simply by adding more to achieve the recommended total depth in inches, without removing existing insulation.

Should I remove old blown-in insulation?

Your insulation needs to be removed along with the droppings, as it’ll carry some of its toxicity if left in your attic. Removing old insulation and replacing it with new ones will not only rid your home from any rodent infestation and mold, but also improve its energy efficiency and overall air quality.

Is cellulose insulation mold resistant?

To make matters worse, although cellulose insulation is mold-resistant, the same cannot be said of the wood that it rests against. Water-soaked insulation sits up against wood walls and can create an area that is susceptible to mold growth.

Which insulation is best for attic?

Fiberglass is one of the best attic insulation materials, and it’s available in various forms. We’ve already discussed the batts and roll forms, both of which involve flat, pre-cut sections. But fiberglass is also available in loose-fill or blown-in form.

How much does it cost to insulate a 1500 sq ft house?

Property owners should expect to spend about $975 to $11,250 to insulate a 1,500-square foot home. Take note that insulation costs may vary and can increase or decrease, depending on whether the insulation comes during or after the construction of the house.

How much does it cost to insulate a 1500 sq ft attic?

How much does it cost to insulate a 1,500 sq ft attic? With average costs ranging from around $1 per sq ft to $5 per sq ft (excluding structural insulation panels as these are best for new installations) expect to pay from $1,500 to $7,500 to insulate a 1,500 sq ft attic.

Does cellulose need a vapor barrier?

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.

Which is better attic insulation blown or rolled?

The Differences Between Blown-in and Rolled Insulation The lower the R-value is, the less effective it will be as insulation – although it will be cheaper as well. … In such situations, blown-in insulation is much more effective since it allows you to easily insulate those hard to reach areas.

What is the R-value of 2 inches of spray foam?

R-Value In 2 Inches Of Spray Foam Open-cell spray foam is vapor-permeable. The R-value ranges from R-3.5 to R-3.6 per inch. The filling of a 2×4 cavity yields about an R-13.

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.

You Might Also Like