How Well Does Drywall Insulate? [Explained]

Homeowners are always looking for ways to improve the insulation in their homes. With the high cost of heating and cooling, anything that can be done to make the home more energy efficient is worth considering. Installing Drywall is one of them and is cheap, but does it also offer enough insulation? 

A Drywall sheet’s primary function is not to insulate, even though it has an R-value of 0.5, which helps with insulation but is not enough as a standalone insulator. A 4-inch wall cavity features an R-value of 15, providing more insulation.

Drywall is generally known to be a “good” insulator. However, there are some misconceptions about how much it really helps with your insulation. Some homeowners might even consider Drywall enough and don’t bother to do anything about insulation, but this might not be such a good idea.

Do Drywall Help In Insulation?

All building materials (including Drywall) offer some degree of R-value – Resistance to Heat Flow. All drywall types (including the regular Drywall) are made of gypsum – a non-combustible mineral. So, Drywall will undoubtedly provide some degree of resistance to heat flow, even if it’s very little. 

However, it’s noteworthy to mention that a drywall sheet’s primary function is not to insulate.

Different wall-covering materials have different properties. While some offer more resistance to heat flow, others do not. A 4-inch wall cavity features an R-value of 15, providing more insulation than a drywall sheet or plywood, which has a much lower r-value.

How Well Does Drywall Insulate?

On average, a 1/2-inch drywall sheet comes with an R-value of 0.5. So, it cannot be used as a standalone thermal insulation material. Keep in mind that the R-value depends upon several factors, including the type of Drywall and its thickness. 

Low R-value does not mean you cannot use this awesome material. In fact, many earthen materials, including natural concrete, dirt, and rocks, display similar low R-values. The good news is that you can use insulation materials, such as sealant products, specialized caulking, and vacuum insulation panels, over your Drywall to achieve higher R-values. 

Types of Insulation for Drywall

Different materials can be used to insulate Drywall. To help you out, below, you have three of the best insulations for Drywall installation projects:

  • Fiberglass Insulation – Using fiberglass batts to insulate Drywall is the most economical and popular method out there. For different projects, fiberglass batts come in different sizes, offering a tight fit between studs. If you use this approach, ensure to add fiberglass insulation in the earlier stages of construction.
  • LooseFill Cellulose – If you want to insulate existing Drywall, loose-fill cellulose is perfect for you. You don’t even have to discard your Drywall! Between the studs, you’ll drill holes near the roof and then insert this insulation using a nozzle. 
  • Spray Foam – Compared to other materials, using expandable spray foam for insulation provides a greater R-value. To save your money and time, it’s advised to use spray foam on exterior walls. 

What Type of Wall Is Best for Insulation?

If you want to stick with Drywall, Type X drywall is the best pick for you. This variation is fire-resistance and usually comes in 5/8-inch thickness. Most builders use Type X walls to soundproof or heatproof a certain room. Some might want to use Drywall of this thickness around a fireplace, but it might not be such a good idea.

Although the Type X drywall has a one-hour fire rating and can still catch on fire, it still has a low R-value (0.5625 for 5/8 gypsum sheets). So, you must insulate a Type X drywall by using fiberglass batts or spray foam.

Alternatively, you can always use another wall-covering material. Below, we have compiled a list of some of the best drywall alternatives with relatively higher R-values:

Fiberboard Sheathing

Regarding R-value, fiberboard sheathing is one of the best alternatives to Drywall. It’s an engineered product made with lumber waste and ground-up wood chips glued together with resin or asphalt binder. This material has more thermal resistance to Drywall, with an R-value of 1.3.

Unlike real wood boards, fiberboard sheathing is free from grains and knots, providing the smoothest finish possible. It’s available in 1/2-inch thickness and in two different sizes: 4×8 and 4×9. In addition, this building board is dimensionally stable, meaning you don’t have to worry about expansion and contraction.

Fiberboard sheathing is certainly not the perfect wall-covering material. It has some cons as well. For instance, it’s vulnerable to wood rot and decay if the moisture content is near 30%. Furthermore, if fiberboard stays in contact with moisture for longer, it can lead to mold and mildew growth.


Next, we have plywood. Although Plywood sheets are less fire-resistant than Drywall, they still have a higher R-value. A 1/2-inch plywood sheet features an R-value of 0.62. In addition, the R-value increases to 1.25 if you use a 1-inch plywood board in your room renovation project.

Plywood is usually made of thin veneers of wood glued together. The boards are made of cross-graining wood, offering directional stability and strength. Compared to Drywall, plywood is more expensive and harder to work with. That being said, it does offer more durability, depending on the select wood.  

Particle Board

Last but not least, we have particle board. Particle boards are also known as low-density fiberboard or chipboard. Just like fiberboard sheathing, this building board is also made of wood chips and synthetic resin. However, particle board features comparatively lower quality than fiberboard.

A 1/2-inch particle board comes with an R-value of 0.53. It can be used to cover interior walls and flooring. Nevertheless, the particle board does not feature uniform density and surface, making it harder to work with! 


What Is The R Value Of 1/2 Inch Drywall?

The estimated R-value of 1/2-inch drywall is 0.5. This might vary depending on your selected drywall type. For instance, a Type X drywall will have a slightly higher R-value than regular Drywall.

Is Drywall Insulation Effective?

Drywall is not mainly known for its insulation properties. Like all other wall-covering materials, it does offer some degree of thermal resistance, but you should use it primarily to insulate. Instead, it’s recommended to use insulation materials over Drywall to make a significant difference in heat flow transfer. 

How Can I Insulate My House Cheaply?

You can use weather-proof strips and caulk to cover any air leaks. Furthermore, it’s advised to use thermal blackout curtains over windows to contain the heat in your home. You can also plug your chimney when it’s not in use or seal your attic air leaks.

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