Steel
Steel is the most budget-friendly entry door material and holds up well structurally — it's hard to kick in and resists fire better than wood. The trade-off is that steel dents, and once the factory finish is scratched or chipped, the exposed metal can rust if it isn't touched up.
Steel doors are typically filled with foam insulation, which gives them solid energy performance for the price. They're a reasonable choice for a straightforward, secure replacement where budget matters more than a wood-look finish.
Fiberglass
Fiberglass is built to mimic the look of stained or painted wood while resisting the warping, cracking, and moisture damage that affects real wood. It doesn't dent as easily as steel and generally requires the least maintenance of the three materials over a 20-plus year lifespan.
It costs more than steel upfront but tends to hold its finish and shape longer in direct sun and temperature swings, which makes it a common choice for south- or west-facing entries that take a lot of UV exposure.
Solid wood
Wood offers a look that steel and fiberglass are designed to imitate — real grain, the ability to refinish or restain over time, and a traditional appearance that some homeowners want on an older or historic-style home.
It also requires the most upkeep. Colorado's low humidity and strong daily temperature swings can dry out and stress a wood door faster than a more humid climate would, so regular refinishing and attention to the weather seal matter more here than they do for steel or fiberglass.
Which fits your project
If budget and security are the priority and you don't mind touching up the occasional scuff, steel is a sound choice. If low maintenance and a wood-look finish matter most, fiberglass is generally the better long-term fit, especially on a sun-exposed entry. If the goal is a genuinely traditional wood look and you're prepared for periodic refinishing, solid wood remains the classic option.
All three materials can be configured with the same range of glass inserts, sidelights, and hardware, so the material decision doesn't have to limit the design.
