What is the R-value of 5 inches of blown in insulation?

Author: Serena Bernhard  |  Last update: Sunday, July 5, 2026

Blown-in insulation has an R value that ranges from 3.2 to 4 per inch depending on the type of material used and where it's installed in the house. This makes it one of the most efficient types of insulation available on the market today.

How many inches of blown-in insulation for R40?

To achieve R-40, we install 12” of cellulose insulation. To achieve R-50, we install 15” of cellulose insulation.

How many inches of blown cellulose insulation is R38?

Using the known R- values per inch of each type of insulation, we know that to install R-38 you need from 10” to 12” of cellulose and 14” to 17” of fiberglass.

What is the R-value of 6 inches of blown insulation?

Blown-in insulation has an R value that ranges from 3.2 to 4 per inch depending on the type of material used and where it's installed in the house. This makes it one of the most efficient types of insulation available on the market today.

What is the difference between R38 and R49?

In colder regions, R49 insulation is essential for roofs and attics to retain heat and lower heating costs during winter. In milder climates, R38 insulation offers sufficient thermal resistance without unnecessary material expenses.

Insulation R-VALUE - What is R-Value?

How thick is R 50 blown insulation?

While conventional insulation requires a thickness of 15 inches to reach an R-value of 50, Rich-E-Board achieves the same result at just 1.5 inches thick. Rich-E-Board can be installed on most roof deck types and can support all conventional low-slope roof systems.

What is the best blown insulation?

Fiberglass is by far one of the most thoroughly tested building materials and can be installed in the form of batt or blown-in insulation. Fiberglass is eco friendly, non-flammable, safe to install and maintains its thermal performance for the life of the building.

Is pink or white blown-in insulation better?

In general, the color of insulation doesn't equal better performance over another color. Whether it's pink, white, brown, or yellow—color doesn't influence dependability, reliability, or the products effectiveness.

How thick is Owens Corning R 38?

10¼ ” thick, R-38C EcoTouch® Thermal Batt insulation prevents moisture damage and help assure long roof life by providing 1" of ventilation air space between the insulation and roof deck.

What is the R-value of 5.5 inches of spray foam?

Spray foam insulation R-value represents the heat resistance for every inch of insulation applied. In essence, a recommended thickness of R-30 is achieved by applying a 5.5-inch depth of spray foam with an R6 rating.

Can you over insulate an attic?

While loft insulation is an effective way to improve energy efficiency and reduce heating costs, over-insulating can lead to several potential issues. Firstly, over-insulation can lead to poor ventilation in the attic, which can cause moisture buildup and increase the risk of mould growth.

Should I remove old attic insulation before adding new?

Do I Have To Remove Old Insulation? Unless your insulation is wet, moldy or infested with pests, you don't need to remove it before adding insulation on top of it. ENERGY STAR® recommends that you inspect your insulation for signs of mold, mildew, moisture and pest infiltration before making this determination.

Which is better, attic insulation blown or rolled?

Blown fiberglass insulation scores an R-value of 3.2 to 3.8, making it slightly less likely than rolled fiberglass to prevent the flow of heat into and out of your house. That being said, though, blown fiberglass insulation isn't meant to cover huge areas like rolled fiberglass insulation.

Should attic insulation be faced or unfaced?

You can use faced or unfaced batting when installing between the roof rafters of finished attic spaces. When using paper or plastic batting insulation, that moisture barrier should face outward toward the attic space. Even if the attic space is unheated, it's typically warmer than the outside air in winter.

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

Thermablok® Aerogel is a revolutionary advancement in thermal technology offering the thinnest insulation available to prevent thermal and cold bridging. Classed as a Super Insulation, Aerogel has the highest insulation value of any known material with the lowest thermal conductivity value of any solid (0.015W/mK).

How many inches of blown insulation is R49?

For attics, you should aim for an R-value between 38 and 49, depending on your specific needs and climate zone. To achieve an R-value of 38 to 49 in your attic, you should aim to install 11 to 14 inches of blow-in cellulose insulation.

What is the best R-value for an attic?

The U.S. Department of Energy recommends attic insulation levels of R-49 to R-60 for most homes in colder climates, and R-30 to R-49 for homes in warmer climates.

How many inches is R38 blown in?

Cellulose has a slightly better R value per inch; R38 is 11 inches of cellulose, but 13 inches of fiberglass.

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

For standard 2x4 walls, which are common in older homes, an R-value of R-15 is considered good, while R-21 is excellent. This can be achieved with high-performance fiberglass batts, dense-packed cellulose, or a combination of cavity insulation and continuous insulation.

Where to rent an insulation blower?

Look for insulation blower rental equipment in The Home Depot Tool Rental Center to help keep your home cool in the summer and warm in the winter. Heating and cooling costs are the biggest portion of utility bills for the average homeowner.

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