Insulation at Wood Studs Vs. Metal Studs

Wood

• Wood has been used for studs as long as homes have been built. Wood is readily available and precut into sizes most typically used for stud installations, such as 2-by-4-inch and 2-by-6-inch sizes. Every piece and type of material used to construct the wall, from the studs to the insulation has what is called an R-value. The higher the R-value, the greater the thermal efficiency of the material to reduce heat loss. The R-value for a 2-by-4 wood stud, for example, is 4.375, according to the Colorado Energy Commission. If you were to add 3½-inch fiberglass insulation around the stud, the insulation would have an R-value of 11, and the total R-value of the wall assembly would increase to 15.375.

Metal

• When metal studs first came on the scene, they were predominately used in industrial and commercial building. Today metal studs are also used in new home constructions and remodeling projects. The ease of use is one of the primary reasons why homeowners opt for metal studs over wood. Metal studs are lightweight and flexible, and you can cut them easily with simple tools like aviator snips. And, you can insulate the studs with the same materials that you use for wood studs --- blanket insulation and rigid foam. A 2-by-4 metal stud has an R-value of 5.5, compared to the 4.375 R-value for a wood stud. By adding a 3½-inch blanket of fiberglass insulation with an R-value of 11, the total R-value for the wall materials would be 16.5, which is 1.375 points greater than wood.

Similarities

• Metal and wood studs are both components of the overall wall assembly of a room. However, neither metal nor wood studs can maximize the energy efficiency of the room alone. Both require an insulation material, such as blanket or rigid foam insulation, to reduce heat loss. And even when insulation is added, it is important to keep in mind that insulation does not block or retard heat from flowing between studs, whether they are made of metal or wood.

Differences

• When insulation is applied to wood or metal studs, it provides what is called “thermal bridging.” The insulation sets up a barrier to reduce cold or warm from reaching the studs to keep the overall thermal efficiency and R-value consistent. Wood has innate properties that enable heat or cold to flow and transfer through its fibers so the overall R-value of a wall assembly is even. Metal studs, on the other hand, retain heat and cold longer than wood. As a result, the heat or cold transfers to the surrounding areas around the metal stud, creating cold or hot spots. If you decide to go with metal studs, consider installing a panel of rigid foam insulation in between the studs and the drywall sheathing materials to stabilize the overall R-value of the wall assembly.