Frame material is the single biggest lever on window replacement cost, and it's also the decision with the longest tail — you're living with it for 20-40 years. Here's how the four main options actually compare.
Vinyl covers roughly 70% of U.S. window replacements because it hits a genuinely good balance: solid energy efficiency (hollow chambers can be filled with insulating foam), zero repainting or resealing, and the lowest material cost of the four. The tradeoff is aesthetics — vinyl comes in a limited color range and can't be painted a different color later the way wood can, and very cheap vinyl can look and perform noticeably worse than a mid-tier or premium vinyl line.
Fiberglass expands and contracts with temperature at almost the same rate as the glass itself, which means the seal between frame and glass stays tighter for longer than vinyl's — vinyl expands and contracts more, which is part of why vinyl seals tend to fail sooner. Fiberglass also takes paint, unlike vinyl, so you get some of wood's flexibility. It costs meaningfully more than vinyl up front; the case for it is a longer service life and less seal failure over 20+ years.
Wood is the best natural insulator of the four and the look most historic districts and HOAs require or expect. It's also the highest-maintenance option — exterior wood needs repainting or resealing on a multi-year cycle, and neglect leads to rot, which is a real repair cost down the line. Many wood windows today are wood-interior with an aluminum- or vinyl-clad exterior specifically to cut that maintenance burden while keeping the interior wood look.
Aluminum is the least expensive material and the strongest per inch of frame, which is why you see it in large commercial-style openings and in mild-climate regions where insulation matters less. Its real weakness is thermal conductivity — bare aluminum transmits heat and cold far more readily than the other three, meaning worse energy performance unless the frame has a thermal break (an insulating strip interrupting the metal). If you're anywhere with real winters or summers, this is the tradeoff to weigh carefully against the lower price.
| Material | Relative cost | Maintenance | Energy efficiency | Typical lifespan |
|---|---|---|---|---|
| Vinyl | $ | Very low | Good | 20–30 yrs |
| Aluminum | $ | Low | Weak (unless thermally broken) | 20–30 yrs (climate-dependent) |
| Fiberglass | $$$ | Low | Very good | 30–40+ yrs |
| Wood | $$$ | High | Best | 30–40+ yrs (with upkeep) |