« Return to BuildingGreen.com

Inline Fiberglass Windows and Doors

Inline Fiberglass, a world leader in pultrusion technology, manufactures fiberglass windows and doors… Read more
(0 User Ratings)
Comments Add a Comment
  • These products are environmentally attractive because they need to be replaced less frequently or their maintenance has very low impact, both of which can reduce costs as well as environmental impact.
    Robust answers on typical service life of products can be hard to come by, however. In GreenSpec we reserve this criterion for products where the material is clearly more durable than alternatives, such as an exceptionally traffic-resistant polyurethane floor finish. We refer to standardized tests for durability when they are available and appropriate.
    We also consider “appropriate durability”: long life is more important in a building envelope than in interior finish materials that will be replaced for aesthetic reasons. Here, reduced maintenance can be particularly important. An example is resilient flooring that doesn’t require regular waxing: an unnecessary use of resources and a health hazard.

  • Before specifying efficient heating and cooling equipment, it’s important to do what we can to reduce heating and cooling loads. Insulation is one of the key products to consider here, but because there are so many insulation products on the market, we look for additional benefits. Examples include cellulose insulation with recycled content, mineral wool insulation with no flame retardants, and fiberglass insulation with no formaldehyde binders. Other products in this area are high-performance windows and glazings, products that contribute to building airtight envelopes, products that reduce thermal bridging, and window-retrofit products.

    With products in this area under constant development, we are always refining our approach. For example, as we have learned about insulation products with hazardous flame retardants and blowing agents that have high global warming potential, we have removed those products from GreenSpec, pending manufacturing changes. We encourage building professionals to pressure manufacturers for those changes through specification language and purchasing decisions.

Alex Wilson
Founding Editor

Inline Fiberglass, a world leader in pultrusion technology, manufactures fiberglass windows and doors. A number of units meet or exceed the 0.30 U-value threshold for GreenSpec with some quadruple-glazed, krypton-filled units rating as low as 0.18. A triple-glazed double hung window in the 900 series, available in five colors and four grill types, can achieve a U-factor of 0.22. The company also licenses its pultrusion technology to other manufacturers.

Composite windows come in two basic types: fiberglass, and wood/plastic composite. Fiberglass has some distinct advantages over wood, vinyl, and metal for window frame and sash construction. As high-quality wood resources become scarce, fiberglass (a composite of polyester resin and glass fibers) is likely to become more common because of its energy performance and durability.

Pultruded fiberglass frame members have a hollow profile that's usually insulated with fiberglass or polyurethane foam. Because the conduction through window frames is a significant source of heat loss, insulated fiberglass frames are an attractive option. The coefficient of thermal expansion of fiberglass is low, very similar to that of glass; limited differential expansion and contraction between the sash and glazing materials puts less stress on the glazing's edge seals. Durability of fiberglass as an exterior material is also good. Most fiberglass windows have factory-applied, baked-on coatings and can be repainted.

To be included in GreenSpec, fiberglass and other composite window lines must include products with NFRC unit U-factors of 0.20 or lower, with windows meeting that threshold being available and actively marketed. Higher U-factors are allowed for products that include significant recycled content.

LEED Credits

EAc1: Optimize Energy Performance

EAp2: Minimum Energy Performance

EQc8.1: Daylight and Views—Daylight 75% of Spaces

EQc8.2: Daylight and Views—Views for 90% of Spaces

IEQc2.4: Daylight and Views

IEQc8.1: Daylight and Views—Daylight

IEQc8.2: Daylight and Views—Views

Ratings and Commentary

Add Comment

Welcome !