Low Emissivity Windows Increase Efficiency

By March 11, 2011Materials

Energy efficiency has become trend in the United States as well as the world. Energy is expensive and to lower the cost of operating a building through the use of energy efficient materials is the smart choice. One item to incorporate into a building would be low-emissivity windows.

The three main types of heat transfer are: convection, conduction, and radiation. All three of these elements apply to all major and minor buildings including modular. These are the sources that construction materials need to combat. Glass has traditionally been a weak point in construction as it has allowed ease of heat transfer via conduction and radiation. Conduction was reasonably solved with double paned windows, however readiation has not been solved until low-e windows started to be manufactured.

Emissivity is a measurement of a material’s ability to reflect or absorb radiant heat in relation to a blackbody or a solid black surface. Where asphalt may have an emissivity of 0.95, aluminum foil would have an emissivity of 0.03 as the foil is more reflective than the asphalt. This means that the foil is more effective against radiant heat because it reflects the energy away from itself instead of absorbing it and allowing for conduction.

Low-e windows use this concept in their design by applying a metallic coating to the surface of the window panes. This allows the glass to transmit visible light, but less infrared light (radiant heat). Not only does it block radiant heat from an outside source, but can also keep radiant heat from the inside from escaping. Therefore, this not only adds to the cooling efficiency of the building during the summer, but also increases heating efficiency during the winter. All of this translates to a 30% to 50% reduction in energy loss through windows at only a 10% to 15% increase in construction material costs.

Modular buildings frequently use low-e windows for the advantage of the consumer, increasing overall energy efficiency of the building and reducing its operating costs. Quality is in the details and Icon Construction utilizes every aspect possible to bring quality and cost savings to our customers.

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