Fiberglass, steel and wood doors differ in surface, finish and care, but the complete door system determines fit, weather sealing and published performance. Compare the exact slab, frame, threshold, weatherstrip, glazing, hardware, finish instructions and warranty. ENERGY STAR-qualified doors use NFRC ratings, with criteria that vary by glazing and climate zone.
Compare complete door systems, not just the visible face. A new slab still needs a compatible frame, threshold, weather seals, hardware and installation.
Compare the material and finish
| Door material | What to check on the exact model |
|---|---|
| Fiberglass | Smooth or woodgrain surface, paint or stain instructions, core and compatible frame |
| Steel | Finish, edge and frame construction, insulation details and how to repair surface damage |
| Wood | Species and construction, finish schedule, exposure conditions and maintenance instructions |
Manufacturers offer different construction and care instructions within each category. Therma-Tru, for example, describes its fiberglass entry-door options and provides a product-specific material FAQ. Review the exact series and warranty rather than generalizing one manufacturer’s performance claims to every door.
Compare the full door system
Ask whether the quote includes the slab, frame, sill or threshold, weatherstripping, glass, lock preparation, finish, trim, flashing and installation. A small mismatch at the rough opening or threshold can change fit and sealing. Check whether the existing frame is square, sound and compatible before deciding on a slab-only replacement.
For energy performance, ENERGY STAR says qualified windows, doors and skylights use NFRC-certified ratings; its door criteria depend on glazing level and climate zone. Use the ENERGY STAR door guidance and the climate-zone finder to compare the exact rated product. A label does not replace correct installation and weather sealing.
Compare door performance with the site’s window rating guide and insulation guide. For removal, sizing and installation bids, review how to hire a remodeling contractor.
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Common questions
Which entry door material is most energy efficient?
There is no material-only answer. Compare the complete door system's documented ratings and installation, and look for an ENERGY STAR label for the climate zone when available.
What is the difference between fiberglass, steel and wood doors?
They differ in surface, finish options and maintenance. Review the exact product's construction, care instructions, warranty and glazing rather than relying on the material label.
Can I replace only the entry door slab?
Check the slab size, hinge and lock preparation, frame condition, threshold and weatherstrip before ordering. A prehung or complete-system replacement may be needed if components do not match.
What ratings should I compare on an entry door?
For a rated glazed exterior door, review its NFRC label and ENERGY STAR climate-zone eligibility. Compare the full door product and installation details.