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A Passivhaus-Certified Skylight Hits the U.S.

Triple-glazed Lamilux skylights get a Class A certification from the Passivhaus Institut in Germany

Posted on Feb 7 2014 by Scott Gibson

A Brooklyn-based retailer of high-performance building components says it will begin stocking a skylight certified by Germany's PassivhausA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. Institut, a move that eventually will shorten the lead time for delivery to U.S. builders to a week or less.

The company, 475 High Performance Building Supply, said its first order of the Lamilux FE Energysave skylights is on the way from its German manufacturer. Once they're in the company's warehouse, the lead time will drop from 10 to 12 weeks to one week or less, said 475's John Druelinger.

Lamilux makes several versions of its skylights. The Energysave is one of several models that 475 will stock but the only one that has won Passivhaus certification. The others are deemed "suitable" but are not certified, Druelinger said.

The Energysave has argonInert (chemically stable) gas, which, because of its low thermal conductivity, is often used as gas fill between the panes of energy-efficient windows. -filled triple glazingWhen referring to windows or doors, the transparent or translucent layer that transmits light. High-performance glazing may include multiple layers of glass or plastic, low-e coatings, and low-conductivity gas fill. and an aluminum frame insulated with expanded polystyrene (EPSExpanded polystyrene. Type of rigid foam insulation that, unlike extruded polystyrene (XPS), does not contain ozone-depleting HCFCs. EPS frequently has a high recycled content. Its vapor permeability is higher and its R-value lower than XPS insulation. EPS insulation is classified by type: Type I is lowest in density and strength and Type X is highest.) insulation. Check your bank balance before ordering one of these skylights, which are available in sizes from 24-in. square to 71-in. square at prices starting at $2,250.

As far as 475 knows, there are no other U.S. retailers that stock Passivhaus-certified skylights.

The skylight has an installed U-value of 0.148 (the glass U-value is 0.105) and Solar Heat Gain Coefficient(SHGC) The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. options of 0.49 and 0.32, the retailer says.


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  1. 475 High Performance Building Supply
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