Is there a big difference between R13 and R15?

Author: Mr. Brook Howell MD  |  Last update: Saturday, November 29, 2025

R15 insulation offers slightly better thermal insulative properties than R13. Some of its formats are a fraction of an inch thicker than R13, making it more effective at helping with energy efficiency. However, the difference is minimal.

Is R13 insulation good enough?

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.

Will R15 insulation fit in a 2x4 wall?

Re: Rockwool Insulation for Basement and Attic (R15 or R23?) You are correct. Yes, the R15 is for 2x4 wall construction and the R23 is for 2x6 wall construction.

What is the difference between Rockwool R15 and R13?

R13 insulation is commonly used in ceilings in moderate climates. It helps to prevent heat loss in the winter and heat gain in the summer, which can improve energy efficiency and comfort. R15 insulation is used in ceilings in colder climates or buildings with high energy usage.

Does R13 help with sound?

R13 batt insulation is typically used to attenuate sound in interior wall cavities.

Comparing R13 Fiberglass to R15 Mineral Wool for Soundproofing Capability

What R-value is best for soundproofing?

The Higher R-Value the Better The higher the number the better job the insulation will do at keeping heat and sound in or out of your home. Cellulouse Insulation has a R-value rating of 3.6-4.0 cubic inches, which is one of the highest ratings in the industry.

What insulation blocks the most sound?

Fiberglass batt insulation is a very popular choice for soundproofing homes and businesses. It is budget-friendly, can be used in any climate zone, provides effective climate control, and is easy to install. Fiberglass batt is great for sound absorption. Thicker and more dense fiberglass batt will perform better.

Is R15 worth buying over R13?

R15 insulation offers slightly better thermal insulative properties than R13. Some of its formats are a fraction of an inch thicker than R13, making it more effective at helping with energy efficiency. However, the difference is minimal. R15 is slightly thicker than R13 for spray foam and blown-in cellulose.

What R rating is better for insulation?

According to the U.S. Department of Energy, R-values for exterior walls in colder climates should be at least R-13 to R-23. In milder climates, a lower R-value may be sufficient. For example, in a moderate climate, an R-value of R-13 to R-15 is typically recommended.

Is fiberglass or rockwool better for soundproofing?

Most wall STC ratings fall between 20 and 65, with 65 being minimal noise transmission. Mineral wool generally has a higher STC rating than fiberglass. However, fiberglass still offers impressive sound-blocking properties.

Is r15 insulation good for garage walls?

Exterior Garage Walls

Typically these will be constructed from standard 2-by-4 studs which will define the amount of insulation that you can have installed. You should be targeting an R-Value of R-13 or R-15 in these areas to properly maximize your insulation in this application.

What is R13 insulation used for?

Known for its sound reduction and easy installation, R-13 batts serve as a thermal barrier, keeping your home comfortable by resisting heat flow. Perfect for modern framing, they ensure minimal obstruction from electrical or plumbing work.

Can wall insulation be too thick?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.

Can insulation R-value be too high?

The optimal R-value for most homes is 30, but you can go as high as 38 if you live in a tropical climate. Anything higher than 38 indicates an over-insulated space. While you might think that too much insulation can't be bad, there are some significant consequences to consider.

Can you double up R13 insulation?

Adding two R-13, 3.5” batts to a 2”x6” (5.5”) wood stud cavity will not provide an R-26. The total of 7” of insulation is reduced in thickness to 5.5” thereby losing the R-value associated with its full thickness.

Is R19 worth it over R13?

R13 insulation is generally more affordable, which makes it an attractive option for budget-conscious projects. However, R19 insulation offers better long-term advantages because of its higher R-value. Why? Because the R-Value translates to a greater energy savings over time.

What is the best insulation for 2x4 walls?

Use R-13 or R-15 kraft-faced fiberglass or mineral wool insulation rolls for 2x4 stud walls. Wall assemblies, especially those in older homes, are built with two-by-four (2x4) studs. The wall thickness will be 3-1/2 inches, not 4 inches. The width of modern 2x4s is 3-1/2 inches.

What is R-15 insulation used for?

The R15 insulation is also commonly used in 2x4 wall assemblies, which is often sufficient for buildings located in milder climates where space is limited, providing a balance between thermal resistance and cost-effectiveness.

Do I need faced or unfaced insulation?

For example, if you need extra soundproofing or don't want to spend time installing a separate vapor barrier, then face may be the best option for you. However, if cost savings are more important than convenience, then unfaced may be the better choice in this case.

What are the disadvantages of R15?

What are the disadvantages of R15 V3? The disadvantages of R15 V3 can include its limited storage space, aggressive riding posture, and relatively high maintenance costs compared to other motorcycles in its segment.

Why is R15 popular?

Yamaha YZF R-15 is one of the most affordable and popular sportbike in the Indian market. The hardware on offer is also quite good. Suspension duties are performed by USD forks in the front and a monoshock at the rear. The engine is a liquid-cooled unit that pumps out 18.14 bhp and 14.2 Nm.

Is R15 uncomfortable?

If you ride this bike for a long time, you'll end up with lower back and wrist pain. This bike is for performance, not to ride comfortably.

Should I use rockwool or fiberglass insulation?

Given a benchmark thickness of 3.5 inches, a batt of Rockwool achieves an R-15 insulation value while fiberglass achieves an R-13 value, giving Rockwool about 15% better insulating ability over fiberglass at the same thickness.

What is the best insulation for exterior walls?

Foam Board or Rigid Foam

Foam boards -- rigid panels of insulation -- can be used to insulate almost any part of your home, from the roof down to the foundation. They are very effective in exterior wall sheathing, interior sheathing for basement walls, and special applications such as attic hatches.

Is faced or unfaced insulation better for soundproofing?

Sound reduction: You can layer unfaced insulation to improve noise reduction between rooms. This option is the best choice because you can use as much as needed, while faced options cannot overlap.

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