Doors comparison
Steel vs Fiberglass Entry Door: Cost Comparison
Both are insulated doors with a foam core, and both outperform a solid wood door on energy. The differences are what happens when something hits the door, and what happens after ten years of sun on it.
Fiberglass
$800 to $4,000 installed
Steel
$600 to $2,500 installed
| Feature | Fiberglass | Steel |
|---|---|---|
| Installed cost | $800 to $4,000 | $600 to $2,500 |
| Dent resistance | Good | Dents permanently |
| Rust | None | Possible where finish is broken |
| Insulation | Good, foam core | Good, foam core |
| Wood-grain appearance | Convincing | Painted look |
| Performance in direct sun | Good | Finish degrades faster |
| Security | Strong, frame and lock decide it | Strong, frame and lock decide it |
| Lifespan | 20 to 30 years | 15 to 20 years |
Fiberglass
- Does not dent or rust
- Holds up well to sun and moisture
- Convincing wood-grain finishes without wood maintenance
- Longer service life in exposed positions
- Costs more than steel
- Can crack under a hard enough impact rather than denting
- Premium finishes push the price toward wood territory
Steel
- Lowest cost of the insulated options
- Very strong against forced entry when properly installed
- Good insulation from the foam core
- Wide availability in standard sizes
- Dents permanently and repairs are hard to hide
- Rusts where the finish is broken
- Finish degrades faster in strong sun
- Reads as a painted door, no convincing wood grain
The verdict
Choose fiberglass for a front door that faces weather and sun, for a wood look without wood maintenance, and where you intend to stay. Choose steel for a side or service door, a garage entry, or a front door under a deep porch where impact and sun are less of an issue, and take the saving. Security is not really a material question: the frame, the strike plate and the deadbolt determine how a door resists forced entry, and a long-screw reinforced strike plate is a cheap upgrade worth doing on any door.
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View on AmazonFrequently asked questions
Is a steel or fiberglass door more secure?
Both are strong, and the material is rarely the weak point. Forced entry usually happens at the frame and the strike plate rather than through the door slab. A reinforced strike plate with three inch screws into the framing, a quality deadbolt and a solid frame do far more for security than the choice between these two materials.
Do fiberglass doors look like wood?
Good ones are convincing, particularly the deeper grain textures that can be stained rather than painted. Cheaper products look like moulded plastic under close inspection. If a wood appearance is the reason you are considering fiberglass, look at the actual product in person rather than in a brochure, since the difference between grades is large.
How much does entry door installation cost?
Installation is typically several hundred dollars on top of the door for a straightforward slab-and-frame replacement in an existing opening. Costs rise if the opening has to be resized, if there is rot in the framing behind the old door, or if sidelights are involved. Rot around the threshold is the most common surprise, and it is worth asking how it would be priced if found.
Should I replace the whole frame or just the door?
Replacing the whole unit, frame and all, gives a better weather seal and a properly square opening, and it is what most installers recommend unless the existing frame is genuinely sound and square. A new slab hung in an old distorted frame will never seal well, which undoes much of the energy benefit of buying an insulated door.