The short answer
Fiberglass and wood are broad product categories. Compare the actual frame and sash construction, cladding or finish, interior appearance, maintenance instructions, rated configuration, parts support, and installation rather than assuming one material has a universal advantage.
| Compare | Fiberglass | Wood or clad wood |
|---|---|---|
| Finish | Product-specific factory or allowed finish | Interior and exterior finish or cladding varies |
| Performance | Exact NFRC label | Exact NFRC label |
Sources
Sources
- Window Types and Technologies — U.S. Department of Energy
- What Makes a Product ENERGY STAR — ENERGY STAR
- Window Energy Performance Ratings — National Fenestration Rating Council