Insulating your home is a vital part of ensuring your energy bill stays low and you stay comfortable. Whether you are building a home from the ground up, finishing an unfinished basement, or renovating a portion of your house, you’ll probably want to make sure your insulation is up to snuff. For this reason, you may wonder if you can fit r19 insulation in a 2×4 wall.
While you can stuff r19 insulation into a 2×4 wall, it is typically not the best way to go about boosting your home’s insulation rating. R19 insulation is meant to fit 2×6 walls. Cramming the insulation into a smaller area might seem like a good idea, but it ultimately won’t result in the r19 rating you would expect.
This may seem counterintuitive, but a bit of understanding will help explain why this is the case. In addition to exploring the mechanics of insulation, we’ll provide you with better ways to increase your home’s insulation.
Why R19 Insulation Doesn’t Work As Well in a 2×4 Wall
The Framing
R19 insulation is typically used in spaces that use 2×6 lumber for framing. Part of what helps the insulation work so well is that the lumber factors into the insulating effect of the walls. Wood has an insulating effect itself, meaning that thicker wooden frames will have better insulation.
2×4 walls typically use r13 insulation. This insulation is thinner, fit to the slightly shallower space created by the thinner frames.
If you attempt to put the thicker r19 insulation into a 2×4 space, you may slightly boost the insulation effect of the wall by a bit, but it still won’t change the thickness of the wood. Since the wood itself is a factor in the insulation rating of the wall, you won’t experience the same kind of insulation you would if you put r19 in a 2×6.
Empty Space
In addition to the boards themselves, the empty space within the wall impacts the insulation rating.
While you may think that squeezing the insulation together would provide more protection from heat transfer, this isn’t the case. Insulation is designed to keep a certain amount of air in the wall with it. This air serves a purpose.
When it comes to heat transfer, the air has different properties than the insulation material. The insulation manufacturers leverage this difference to create an ideal balance between air and fiberglass. The combination of the two provides the best protection against heat and cold.
When you squeeze r19 insulation into a space too shallow for it, you eliminate some of the air intended to stay in the wall. This in turn lowers the actual insulation rating of the wall. The insulation won’t be nearly as effective as it should be.
Better Ways to Increase the R Value of Your Walls
As you can see, stuffing r19 insulation into a 2×4 space isn’t the best way to insulate your space. Here are a few options you should consider instead.
Install 2×6 Framing
If you’ve already bought the r19 insulation or are simply set on using r19, the best option is to use 2×6 framing in your walls.
If you are building a home or expanding your space, this option is particularly advisable. While it may cost a bit more, going with 2×6 framing from the outset is a smart investment. The thicker lumber will keep your space insulated better than using standard 2×4 framing.
If you are dealing with an already-built space, replacing the frames is going to be expensive and tedious. Regardless, it may be of benefit to you in the long run. 2×6 frames will ultimately allow you better insulation, saving you money on your energy bills moving forward.
Use R15 Fiberglass Insulation
If you don’t want to entirely redo your walls’ framing, you can achieve a higher r-value using better insulation meant for 2×4 walls. Fiberglass insulation for 2×4 walls is available up to a rating of r15.
While still not as high as r19 insulation, r15 will provide a slight upgrade compared to the standard r13 used in 2×4 walls. If you are just looking for a general reduction in your energy bill, this solution may be right for you.
This is an especially good option if you’re working on a tight budget. Fiberglass insulation is the cheapest option. While r15 will be slightly more expensive than r13, it won’t be nearly as expensive as entirely redoing your framing.
Use Polyurethane Insulation
If neither of the above appeals to you, you can boost your R value by using polyurethane insulation instead of fiberglass.
Polyurethane is a foam that is filled with little pockets of gas. The combination of the foam itself and the gas within is highly resistant to heat transfer. It can provide far higher levels of insulation than fiberglass of the same thickness.
When considering polyurethane insulation, you have a few options to choose from. Rigid foam installations can be installed yourself, as they come in pre-shaped bundles. Open and closed cell foam installations must be done by a professional. These applications are sprayed directly into the wall, a process that requires expertise to do correctly.
Polyurethane insulation is a fair deal more expensive than fiberglass. That being, it is an investment that pays for itself over time, as your energy bill will be significantly lower when using polyurethane. Depending on the type you use, polyurethane insulation can have an R value as high as 28.
Related questions
What r-value can you get in a 2×4 wall?
The r-value of your 2×4 wall will depend on what type of insulation you use. If you stick with standard fiberglass, the highest available insulation will be rated r15. If you invest in polyurethane, you can get insulation rated as high as r28.
Is r19 good for walls?
R19 insulation is generally considered great for preventing heat transfer and keeping energy bills low. That said, the higher the r-value, the better. Some options provide r values higher than r19, meaning they will better prevent heat and cold from entering your home.
