Not quite. Polyurethane features superior thermal insulation with a factor of RSI: 2.8 (R:16). In addition, since polyurethane adheres better to door surfaces, it provides twice as much resistance to flexion as polystyrene (Styrofoam) in a comparable door. Entrance doors are also insulated with polyurethane foam. Polystyrene is the material used to make coffee cups.

You should be able to easily lift the door open with one hand, regardless of its size or the material it is made of.

If you notice the door is heavy and hard to open, this could mean the springs are no longer counterbalancing the door properly and may need to be replaced

When the safety reversing sensors are misaligned the door will not close from the remote control and the garage door opener lights will flash. Locate the receiving sensor, which has a green LED. The receiving sensor LED will be off, dim or flickering, indicating the sensor is out of alignment. To align the sensors simply loosen the wing nut on the receiving sensor. Move the sensor around until the LED is glowing steadily and not flickering. Tighten the wing nut. When the receiving sensor LED is properly aligned it will glow steadily.