What type of insulation improves the energy efficiency of a foundation wall?

Sheet insulation is an effective solution for improving the energy efficiency of a foundation wall because it provides a continuous layer of thermal resistance, minimizing thermal bridging and air leakage around the edges where traditional insulation might be less effective. This type of insulation typically comes in large panels made of rigid foam materials, such as expanded polystyrene (EPS), extruded polystyrene (XPS), or polyisocyanurate, which can be easily installed against the foundation wall.

The rigid panels have a high R-value per inch of thickness, meaning they provide excellent insulation without taking up excessive space. Their solid structure also contributes to moisture resistance, which is crucial for foundation applications, helping to prevent moisture-related issues such as mold and rot.

Other forms of insulation, like loose-fill insulation or fiberglass batts, may not be as effective when applied directly to foundation walls. Loose-fill insulation can settle over time, leading to reduced performance, and fiberglass batts might not create a seamless thermal barrier on uneven surfaces. Cellulose insulation, while effective in other applications, may not perform as well in foundation walls primarily due to its susceptibility to moisture absorption.

In summary, sheet insulation's characteristics make it particularly well-suited for foundation walls, emphasizing its ability to deliver a high level