Polyurethane Insulation Material
Polyurethane foam insulation carries a gas in its cells that have low-conductivity. With a relatively large thermal resistance, polyurethane insulation boasts R-values that range from 5.5 to 6.5 per inch.
Polyurethane foam insulation has been made available in both open-cell and closed-cell formulas. Closed-cell foam has a high-density and is filled and closed with gas to help it expand into the space around it. By contrast, open-cell foam has a lower density and is filled using air, giving it a texture that is spongy, and has a lower overall R-value.
As with polyiso foam, closed-cell polyurethane insulation has an R-value that drops over time due to thermal drift. This usually takes place within two years following its manufacturing but remains unchanged afterwards unless it becomes damaged.