If you’ve ever gone, you must have been asked to specify two types of -required values: R-values and U-values. Sounds familiar?
The U-value of an insulation material indicates its insulation performance, whereas the R-value is indicative of thermal resistance. For the sake of this article, we’ll look at R-values. If you live in colder regions or need insulation for areas in your home that require a higher amount of thermal protection, your choice will be between R19 and R30 insulation.
Since 30 is a higher number than 19, it stands to reason that R30 insulation is more effective at providing thermal protection. However, more efficiency doesn’t always translate to ”best choice.” So, what does? Let’s discuss.
What Is R19 Insulation?
As the name tells us, R19 insulation is any insulative material providing an R-value measurement of 19. You can find fiberglass batts and rolls with R19 in most hardware stores. It’s usually made of fiberglass and recycled paper, but some use mineral wool or cellulose material.
Where Is It Used?
According to the US Department of Energy, R19 insulation is ideal for use in climate zones 1 to 7. Let us explain climate zones a bit here.
A climate zone includes the geographical location and the specific weather patterns of that region. The US Department of Energy divides the nation into eight different climate zones, each with its own insulation requirements.
The authority recommends using R19 insulation in uninsulated floors in Zone 3 and Zone 4. You can also use this insulation material in uninsulated wood-frame walls, although the recommended requirement is a little higher, up to R20.
R19 insulation can also be used in Zone 1 in the attic, but only if you already have about 3 to 4 inches of existing attic insulation.
Besides the climate zones, you can also consider lumber thickness to determine if R19 insulation is the right fit for your project. R19 insulation is just a little over 6 inches thick. That makes it perfect for construction projects using 2 x 6 inch lumber.
The R19 insulation fits into the walls tightly in such applications. As a result, it prevents airflow through the plywood in the walls.
R11 Insulation Depth
R19 insulation is 6.75 inches thick. However, the insulation material you select may be slightly different in terms of thickness and composition. For example, if you opt for fiberglass loose-fill insulation, it will have a thickness of 6.3 inches, while batt insulation has a depth of around 5.2 inches.
What Is R30 Insulation?
R30 insulation is much thicker and provides better insulation than R19 or R11 insulation. It is 9.25 inches thick, making it ideal for use in most climate zones.
You should consider this insulation material if you are looking for excellent protection against cold weather, especially in crawl spaces and attics.
Where Is It Used?
The US Department of Energy recommends R30 insulation for uninsulated floors in all climate zones except Zones 7 and 8, where the recommendation is R38. Plus, you can use R30 insulation in an uninsulated attic in Zone 1.
If your attic already has 3 to 4 inches of insulation, you can use R30 insulation in Zones 1, 2, and 3. According to Home Depot, R30 insulation is also suitable for floors and crawlspace in Zones 4 through 7.
Unfaced batts with an R-value of 30 can also be used on roofs and ceilings. Or, you can use them to insulate exterior and interior walls.
”Unfaced” means that the insulation material does not have a vapor retarder, which usually comes as a plastic or paper ”facing.” Such insulation is ideal for new constructions, especially in the basements and floors.
R30 insulation batts also fit between metal and wood framing cavities. Likewise, if you have furring channels, you can use R30 insulation in them.
R11 Insulation Depth
The minimum thickness of R30 insulation is 9.3 inches. Again, the thickness can differ based on the material type. In some cases, you may have to make do with 8.33 inches, while in others, you may be able to get up to 11.7 inches.
Which One Should You Choose: R19 or R30?
When it comes to choosing between two insulation ratings, you should keep the following types of factors in mind: personal, regional, and economic. Here’s what to consider.
How cold is your region? If you occasionally have temperatures below -20 F, you should go with R30. After all, you need an insulation material that can keep you warm and safe during the coldest winter months. Plus, an insulation material with the right R-rating will also help lower your energy bills.
However, if your area doesn’t get as cold, R30 will be too much. You’ll end up spending all that extra money on something that won’t benefit you. In this case, R19 will be a better option.
It’s best to check the US Department of Energy’s website for your specific climate zone before making a purchase.
Obviously, R30 insulation is more expensive. If you’re on a tight budget, go for R19. It’s a more affordable option that also provides good insulation values.
Do you have a preference for blown-in insulation or batt insulation? Typically, the insulation thickness differs across material types. For example, R30 insulation has a thickness of 10.9 inches in blow-in rock wool but only 7.5 to 8.33 inches in foam board insulation.
The thickness is even lower if you get closed-cell spray foam insulation, at just 4.25 to 6 inches. You could get the same or more with R19 insulation fiberglass batts.
If you need a specific insulation thickness, check the material type before making a purchase.
Is R30 Insulation Better Than R19?
It’s no surprise many people think since it has a higher R-rating, R30 must be better than R19. But it isn’t always the case. Depending on your climate zone and budget, either insulation material could provide you with a decent thermal envelope for your home.
When Should You Upgrade From R19 to R30?
You know it’s time to upgrade when R19 insulation isn’t doing much for your utility bills or comfort. When upgrading, consider adding a moisture and vapor barrier along with the insulation upgrade. It will help prevent further damage caused by moisture accumulation in your walls.
You may also want to upgrade if you’re redoing your attic. Maybe you didn’t have enough budget the last time but aren’t constrained this time around. R30 could meet your area’s weatherproofing requirements better.
Alternatively, if you want to increase the energy efficiency of your home without spending too much money, options like air sealing and weatherstripping will do the job.