Does R-value vary significantly by insulation type or brand?

Types of Insulation and R-Value

R-value is a measurement of thermal resistance, and it varies significantly among different insulation types. Fiberglass batts have an R-value of R-2.9 to R-3.8 per inch, while spray foam insulation ranges from R-3.5 to R-6.0 per inch. Radiant barrier insulation, on the other hand, has an R-value of R-2 to R-4, depending on the material.

Factors Affecting R-Value

The R-value of insulation can also be affected by factors such as moisture content, temperature, and aging. For example, fiberglass batts can lose up to 30% of their R-value when exposed to high humidity. Additionally, some insulation materials, such as open-cell spray foam, can continue to expand and improve their R-value over time. When selecting insulation, it’s essential to consider these factors and choose materials that can perform well in a variety of conditions.

Measuring and Verifying R-Value

To ensure that insulation meets its claimed R-value, it’s crucial to verify it using a reliable method. One such method is to use a thermal imager or a thermal conductivity meter to measure the R-value of a specific insulation material. This can be done on-site or in a laboratory setting. Some insulation manufacturers also provide third-party verification of their products’ R-values, which can provide an added layer of assurance for builders and homeowners.