All closed-cell polyurethane foam insulation made today is produced with a non-CFC (chlorofluorocarbon) gas as the foaming agent. Some polyurethane foam combines with a HCFC gas. These foams have an aged R-6 per inch thickness. Their density is generally 2.0 lb/ft3 (32.0 kilograms per cubic meter [kg/m3]).
Low-density, open-cell polyurethane foams (0.5 lb/ft3 [8 kg/m3]) have an R-value of about R-3.6, which doesn’t change over time. These foams are similar to conventional polyurethane foams, but are more flexible. Some low-density varieties use carbon dioxide (CO2) as the foaming agent.
Polyurethane Insulation Materials
Polyurethane is a foam insulation material that contains a low-conductivity gas in its cells—usually a hydrocarbon or hydrochlorofluorocarbon (HCFC). The high thermal resistance of the gas gives polyurethane insulation materials an R-value typically around R-5.5 to R-6.5 per inch.
Polyurethane foam insulation is available in closed-cell and open-cell formulas. With closed-cell foam, the high-density cells are closed and filled with a gas that helps the foam expand to fill the spaces around it. Open-cell foam cells are not as dense and are filled with air, which gives the insulation a spongy texture.