What type of insulation is manufactured in sheets and has higher R-values per inch?

Rigid insulation is the correct answer because it is specifically designed to be produced in sheets with a dense structure that provides significant thermal resistance. The R-value, which measures the insulation's resistance to heat flow, is typically higher per inch compared to other forms of insulation, such as loose fill or spray foam. Rigid insulation is often made from materials like polystyrene or polyisocyanurate, both known for their effective insulating properties.

In contrast, loose fill insulation consists of small particles that fill spaces but generally have lower R-values per inch due to the air gaps created between those particles. Flexible insulation, usually made from fiberglass or other soft materials, is designed to fit into spaces but may not achieve the same high R-value per inch as rigid insulation. Spray foam insulation, while providing a good air seal and decent R-value, can be more variable in its performance depending on the application and thickness. Therefore, rigid insulation stands out for its high R-value and sheet form, which makes it particularly useful in many construction applications.