Whats the difference between expanded polystyrene (EPS) and polyurethane?
A. Insulated garage doors typically contain either expanded polystyrene (EPS) or polyurethane. All Amarr insulated garage doors contain CFC-free EPS as opposed to foamed-in-place polyurethane. When comparing only R-values, it might be easy for one to be persuaded to purchase a door insulated with polyurethane. After all, they have a higher efficiency rating. However, polyurethane has some inherent disadvantages that you should be aware of. 1) Degradation: polyurethane has been known to degrade over time. This causes the R-value to actually decrease, sometimes by as much as 25%, as the door ages. Polystyrene insulation is permanent because the cellular structure of it contains only stabilized air. Its value does not decrease as it ages. 2) Environmental concerns: polyurethane contains harmful CFCs that can adversely affect the environment. Polystyrene is not only CFC-free, but is recyclable, therefore reducing the amount of non-biodegradable waste. 3) Delamination: some manufacturers of
