R19 vs R13 Insulation: Differences

Insulation is installed in walls, ceilings, and basements to save costs on air-conditioning and heating, typically by homeowners. However, deciding which insulation to get for your home can be difficult, especially when facing technical terms such as the R-Value. Simply put, the R-value of insulation is a tool to judge the thermal insulation performance of the insulation you’re picking. As a rule of thumb – the greater the R-value, the better the insulating ability. So, you may automatically assume that R19 is better than R13. But that, in no way, means that you shouldn’t consider R13 insulation at all. 

It’s important to remember that each insulation has its benefits in its domain, and its usage differs on the parts of your home. Thus, you might come across R13 in some places and R45 in others. Nonetheless, the most popular insulation values are R19 and R13. 

To help you get a clearer picture of and differences between R19 and R13 insulation, read the table below:

R19 Insulation R13 Insulation
Recommended for 2×6 walls Recommended for 2×4 walls
It can be used in both – the southern and northern regions of the US for insulating walls.  It can be used in southern regions of the US but is not recommended in northern regions. 
Commonly used to insulate outer walls of newer buildings Commonly used to reduce sound in interior wall cavities 
The standard fiberglass batt is 6.25” thick The standard fiberglass batt is 4” thick 
The average cost range per square foot is $0.90 – $1.25 The average cost range per square foot is $0.60 – $1.00 
R19 vs R13 insulations

Now that you know the basic and most important differences between these two, it’s time, we get you acquainted with them in detail; so you can make better choices for your home. 

Where are R-13 and R-19 used? 

The application of R19 is most common in vertical walls framed by 2×6 studs, as also recommended by the US Government. When done with installing R19, sealing is the key as you don’t want air to escape; therefore, make sure to air seal, especially your exterior walls, before insulating. Leaving even minute leaks can defeat the whole purpose of having thick insulation like R19. Insulation, plus air seal, calls for great efficiency and effectiveness. On the other hand, most older buildings and homes are built with 2×4 studs. Since 2×4 walls can hold R13 batts fairly well, it is advisable to use R13 in 2×4 walls.  

In numerous regions of the country, it is beneficial to use R19 insulation in the outer walls of new and fresh construction projects. Additionally, homes also use R19 in their attics and basements as insulation slows down the transfer of heat; consequently, that seems to be most successful when applied to ceilings and exterior walls. R13, however, is more typically used in cavities of the interior walls. Because noise transfer from one area to another is reduced by R13, such is most applicable indoors, permitting the house to be less susceptible to unwanted disturbances transmitting from here to there. Some manufacturers make insulation batts with a 90% Noise Reduction Coefficient (NRC) that absorbs 90% of the outside noise and reflects 10% of it. 

Does your location matter when choosing R13 or R19? 

Yes, it does! Some houses are in colder regions, and some in hotter. Where it is colder, there’s more insulation required and vice versa. Hence, the US Department of Energy has rated R13 ‘good’ for southern regions but has claimed it as unadvisable for houses in the north. By itself, R13 doesn’t provide enough insulation in colder regions and then has to be used with extra layers of insulation to make it sufficient. R13 is also good at managing moisture, making it a close-to-perfect pick for hotter regions where humidity is a common occurrence. 

Nonetheless, R19 is ranked great for southern regions as it has a more advanced ability to provide thermal insulation than R13. Also, R19 does not limit you to hotter areas, making it useable in the northern parts of the country. But, in extremely cold weather, R19 may also fall short and can be upgraded to R21 for better usage. All in all, R13 is good at reducing cold temperatures, while R19 is good at resisting cold temperatures and retaining heat inside. 

Insulation thickness needed to achieve R13 or R19

Each insulation type uses different materials according to the capabilities of each one of them, and their thickness also varies accordingly. Fiberglass, spray foam, cellulose, foamboard, and Rockwool are five materials used for R13. In addition to these four, aerogel is used for R19. As afore-mentioned, each R-value signifies a varying thermal insulation ability; hence, the thickness of each of these differs. 

Material R13 Thickness (inches) R19 Thickness (inches)
Fiberglass (batts) 3.5 6.25
Fiberglass (loose-fill) 4.3 6.3
Spray foam (closed cell)  2.17 3.1
Spray foam (open cell) 3.61 5.2
Cellulose (loose-fill) 3.82 5.5
Rockwool (batts) 3.61 5.2
Rockwool (loose-fill) 4.33 6.3
Foam board 2.6 3.8
Aerogel
2.1 

With each of the thicknesses, the cost differs too; nonetheless, the average costs have been stated earlier. 

Conclusion

With that said, if you’re struggling to choose between R13 and R19, narrow down your location, purposes, structure, and budget, and pick the perfect composition for yourself. Both are excellent in their ways, and they’ll both bring you benefits if you aim for efficiency and effectiveness. 

Charles John

A novice DIYer who learns about home ventilation. I am a mechanical engineer and have a basic knowledge of HVAC systems but I learn continuously to make myself the best blogger in that space.

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