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Geneo High-Performance Windows

Wasco Windows offers Geneo windows, a range of high performance windows made of a glass-fiber reinforced PVC… Read more
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  • 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

Wasco Windows offers Geneo windows, a range of high performance windows made of a glass-fiber reinforced PVC. The windows achieve a U-factor ranging from 0.14–0.17, and meet the Passivhaus standard, according to the company. As with all Wasco windows, Geneo windows feature Cardinal Glass and are available double- or triple-glazed with argon fill and a non-metal spacer for increased thermal performance. Wasco covers Geneo Windows with a lifetime warranty.

Plastic windows come in both ABS and vinyl (PVC). Even though PVC is particularly loathed by environmentalists, energy performance is GreenSpec’s primary green consideration for windows, and some vinyl windows offer exceptionally strong energy performance, often with competitive pricing. The PVC used in windows has life-cycle concerns, but is not considered a significant human health issue during the use phase. PVC does present the risk of dioxin generation during an accidental fire or incineration at the end of the product's life, while ABS does not contain chlorine and so does not present that risk.

New developments in window technology enable today's products to far outperform those of a few decades ago. Among the improvements are multiple glazing layers, low-conductivity gas fills, better seals on insulated glazing units, heat-reflective (low-emissivity) coatings, advanced weather-stripping, and new frame systems.

Low-emissivity coatings which allow short-wavelength solar radiation (sunlight) to pass through but reflect long-wavelength radiation (heat) back into the conditioned space are now standard options from all major window manufacturers. Further improvement in energy performance is achieved with triple-glazing and multiple low-e coatings; sometimes an additional glazing layer is provided as a suspended polyester film.

Vinyl has a tendency to expand and contract to a high degree with temperature changes. While window manufacturers claim that their designs minimize this issue, consumers should be aware of this potential downside to vinyl, and select high-quality windows that are durable and airtight.

Plastic windows listed by GreenSpec must achieve an NFRC-certified unit U-factor of 0.20 or lower, or be Passivhaus certified, and not only be available, but also actively marketed.

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

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