Once you have decided on an insulated garage door, there is one more fork in the road: what is inside the sandwich. Two foams dominate the market, and door brochures do not always make the difference plain. Here it is without the gloss, the way we explain it at the counter in Kent.
What is the actual difference between the two foams?
Polystyrene is rigid foam board, the white material you know from coolers, cut to fit and placed inside the panel. Polyurethane is injected as liquid and expands to fill every corner, bonding to both steel skins as it cures. That bonding is the underrated part: the panel becomes a single rigid unit rather than skins with a loose filling.
How do they compare where it counts?
- Insulation per inch: polyurethane roughly doubles polystyrene. Same panel thickness, about twice the R-value.
- Stiffness: the bonded polyurethane core resists dents, sag and wind flex noticeably better. In practice that means a flatter door in year fifteen.
- Noise: the bonded core deadens both street noise and the sound of the door itself running. Polystyrene helps; polyurethane is the quiet one.
- Cost: polystyrene is the value play, and against a hollow door it is still a big upgrade.
Which one should a Puget Sound homeowner pick?
Attached garage anywhere from Renton to Puyallup, especially with rooms above: polyurethane, and you will feel why every winter. Detached garage, storage duty, or a tight budget that would otherwise mean skipping insulation entirely: polystyrene is honest value, not a consolation prize. Both are available across the Clopay residential collections we install as a Master Authorized Dealer.
Frequently asked questions
Which is better in a garage door?
Polyurethane insulates about twice as well per inch and stiffens the panel. Polystyrene costs less and still clearly beats uninsulated.
What R-values do they produce?
Polystyrene doors typically run R-6 to R-9; polyurethane doors R-12 to R-18.
Does polyurethane make the door heavier?
Slightly. Springs matched to the exact door, standard on a professional install, make the weight a non-issue.
Want to see both constructions in person? Visit the Kent showroom, call (253) 859-2318, or request a quote and we will bring samples to the driveway.