Fiberglass doors typically cost more than steel doors but are more resistant to weather and last longer. Fiberglass doors provide better insulation and have more design options. Neither type of door requires much maintenance.
The inner frame is usually the same for all types of doors, consisting of wood and a foam core. The outer skin of the door is the part made from different materials based on the type of door. Besides fiberglass and steel, wood doors are also available.
Although steel doors are the strongest as a barrier, their advantage over fiberglass doors in that regard is relatively minor. Fiberglass doors handle normal wear and tear better, according to Consumer Reports. Dents, which are hard to fix, sometimes occur in steel doors that are heavily used. Fiberglass doors are resistant to dents and scratches, and they only crack under very large impacts. Inclement weather, such as wind and rain, significantly reduces the lifespan of steel doors but not fiberglass doors.
Although fiberglass doors insulate more effectively, both doors provide adequate insulation. Glass panels reduce a door's insulation ability.
Steel doors either have a smooth appearance or have panels. Fiberglass doors either have a smooth appearance or an embossed wood grain. With staining, a fiberglass door mimics the appearance of wood.