The foam type with the highest R-value is polyisocyanurate.
Understanding R-Value in Insulation
The R-value measures thermal resistance, indicating how well an insulation material resists the flow of heat. A higher R-value signifies better insulating performance, meaning the material is more effective at preventing heat transfer, keeping your home warmer in winter and cooler in summer.
Leading Foam Insulation Types and Their R-Values
Rigid foam board insulation is a highly efficient option, available in various materials, each offering different levels of thermal resistance. Among these, polyisocyanurate consistently provides the highest R-value per inch.
Here's a comparison of common rigid foam board insulation types:
| Foam Type | Typical R-Value Per Inch |
|---|---|
| Polystyrene | R-3.8 to R-5.0 |
| Polyurethane | R-5.5 to R-6.5 |
| Polyisocyanurate | R-5.6 to R-8.0 |
As shown, polyisocyanurate stands out with the highest R-value, reaching up to R-8.0 per inch. Its superior thermal performance makes it a preferred choice for maximizing energy efficiency in various building applications.
Applications of High R-Value Foam
Due to its exceptional R-value, polyisocyanurate rigid foam is particularly well-suited for demanding insulation applications where space is limited or superior thermal performance is critical. Its common uses include:
- Foundations and Basement Walls: Its high R-value helps prevent heat loss through the ground and maintain a comfortable, dry basement environment.
- Exterior Walls: Applied as continuous insulation, it reduces thermal bridging and significantly improves the overall energy performance of a building envelope.
- Roofs: It's frequently used in low-slope and flat roof systems to provide high thermal resistance and support waterproofing membranes.
- Attics: In certain applications, it can be used to create an insulated attic space, especially in cathedral ceilings.
Choosing high R-value foam like polyisocyanurate contributes to lower energy bills, enhanced indoor comfort, and a reduced carbon footprint for your property. For more information on insulation materials and their R-values, you can refer to resources like the U.S. Department of Energy.
