green-building-newsheader image
0 Helpful?

Attic Stairs for High-Performance Houses

An Austrian company is manufacturing a pull-down stair certified by the Passivhaus Institut

Posted on Jun 8 2017 by Scott Gibson

A New York-based retailer is offering a pull-down attic stair designed to solve a knotty problem in high-performance houses with unconditioned attics.

Unless a builder cobbles together a well-sealed attic hatch, or builds an insulated and air-sealed door and stairwell, the hole in the attic floor will mean a lot of wasted heating and cooling energy as well as serious air leaks.

The Klimatec 160, made by the Austrian company Wippro, offers builders a way to insulate the opening with 6.3 inches of extruded polystyrene insulation for an advertised R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of 26 and an installed whole-unit R-value (taking the frame into account) of about R-17. An optional hatch adds 2 3/8 inches of insulation for another R-9.7.

The retailer, 475 High Performance Building Supply, sells the unit for $1,195; the optional lid is another $300.

The stair is certified by the 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 in Germany. It fits in a rough opening 55 1/8 inches by 27 9/16 inches, and has a staircase length of 98 1/2 inches to 118 1/2 inches.

A full set of specs is available at . The Passivhaus Institut certificate is available .


Tags: , , ,

Image Credits:

  1. Wippro

Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!

там

нитяные шторы

続きを読みます