Why MARVIN fiberglass for replacement windows and PATIO doors?

Marvin pioneered the use of fiberglass for replacement windows and doors over 20 years ago. We go even further with Ultrex® fiberglass - our proprietary fiberglass solution that offers unsurpassed durability and timeless style.

THE ULTREX ADVANTAGE

We use Ultrex fiberglass for unmatched performance

8x
Ultrex® is 8x stronger than vinyl.
87%
Ultrex® expands 87% less than vinyl.
48,000
48,000 hours of sun can’t fade the superior finish of Ultrex® fiberglass.1

1. Average sunlight exposure per 10 years.

THE ULTREX ADVANTAGE

Replacement Window Material Comparison

Compare Marvin Replacement
Vinyl
Vinyl/Wood Composites (Fibrex)®
Marvin Ultrex® Fiberglass
Why Marvin?
Strength
Good
Better
Best
Ultrex is 8x stronger than vinyl and 3x stronger than Fibrex.
Stability
Good
Better
Best
Ultrex’s low expansion rate means our windows and doors stay tight and true for a weathertight seal.
Durability
Good
Better
Best
Marvin’s acrylic finish is 3x thicker than the competition and resist scraches, fading and chalking.

Fibrex® is a registered trademark of Andersen Corporation.

THE ULTREX ADVANTAGE

Bigger views with fiberglass windows

Because of Ultrex’s incredible strength, we can build narrower frames — so you get more incredible views for your money.

Ultrex

Specifically designed to resist warping and weathering in any conditions for long-lasting durability.
vs.

Vinyl

Can expand and contract under everyday conditions— potentially compromising your home’s integrity.

Proven strength
for peace of mind

Compared to other materials, Ultrex fiberglass is the strongest window and patio door framing material in the replacement industry.
Ultrex is 8x stronger than vinyl and 3x stronger than Fibrex
We test the strength of Ultrex fiberglass so you don’t have to worry about your home. The results speak for themselves. Ultrex resists bending and flexing - that's confidence Fibrex and vinyl simply can't match.
3,000
ULTREX
808
WOOD/VINYL COMPOSITE (FIBREX)®
385
VINYL
0
1,000
2,000
3,000
Flexural Modulus (KSI) — ASTM D790

Stability for a fit that never quits

Ultrex expands at virtually the same rate as glass, so our windows and patio doors stay tight and true.
Ultrex expands 87% less than vinyl and 75% less than Fibrex
We test the material stability and expansion of Ultrex fiberglass. Ultrex’s proven stability makes Marvin Replacement’s windows and patio doors resistant to leaks, seal failures and stress cracks that can compromise energy efficiency and long-term performance.
0.4
ULTREX
0.6
GLASS
1.3
ALUMINUM
1.6
WOOD/VINYL COMPOSITE (FIBREX®)
4.0
VINYL
0
1.0
2.0
3.0
4.0
Expansion and Contraction x10-5 in/in/F — ASTM D696

A fade-resistant finish

Our proprietary acrylic finishing process is unlike anything else in the industry. With a finish that’s 3x thicker than competitive options, Ultrex fiberglass resists scratches, fading, chalking, chipping, denting or peeling to retain its original beauty. Best of all, it is virtually maintenance-free.
ULTREX
Smooth, thick finish
COMPETITOR
Rougher, thinner finish

MARVIN REPLACEMENT:

Ultrex fiberglass windows and doors can save you money on energy bills

The low thermal conductivity and superior performance of Marvin Replacement windows and patio doors built with Ultrex fiberglass combined with a selection of energy-efficient glass options can help save money on your energy bills.

Savings reflects installing ENERGY STAR certified products compared to non-certified when replacing single pane windows based on the average savings among homes in modeled cities.