Another reason not to build glass towers: They are not resilient
In the years we have covered the Passivhaus concept, the main selling point has been the energy saved through a simple concept: lots and lots of insulation, careful detailing and siting, no green gizmos needed. However, the recent New York City Buildings Resiliency Task Force Report, covered on TreeHugger here, points out another big benefit of super-insulation: Resilience. The report notes:
Issue:Utility failures often disable heating and cooling systems, leaving interior building temperatures dependent on whatever protection is provided by the building's walls, windows and roof.
When power was lost in parts of New York City—in some places for several weeks—there was recognition by the City that conditions could get pretty dire very quickly, especially in high-rise residential buildings during hot weather (projected to become a more common occurrence). In the summer, temperatures may rise quickly to dangerous levels, and in the winter, temperatures will fall. We can refer to these as drift temperatures.
We are not talking about comfort here, we are discussing survivability. Alex continues:
Really well-insulated buildings will maintain the habitable conditions much longer than conventional buildings—perhaps even indefinitely. A home built to Passive House standards (a rating system for ultra-low-energy buildings that emerged in Germany and is gaining popularity here) incorporates not only very high insulation levels, super-high-performance windows, and very low air leakage, but also some passive solar gain.
In most places, such a home will never drop below 55°F or perhaps even 60°F in winter, even with no supplemental heat. And in the summer if such a house is wisely operated (closing windows during the day, for example), it should maintain temperatures significantly cooler than outdoors.
It's not just about energy savings, it's about survival.
Where I live in Toronto, almost every new building is clad in floor to ceiling glass with an R value of maybe 3 on a good day. They usually have tiny window openings mechanically limited to four inches maximum opening for childrens' safety. If the power went out in winter they would be at ambient outdoor temperature in a couple of hours; in summer any south facing unit would be uninhabitable. These buildings rely on a continuous supply of heating or cooling to be livable. When that goes, the occupants might as well pitch a tent on the balcony.
Surely after the events of Superstorm Sandy or the Great Flood of Alberta, resilience is no longer an optional extra but a necessity that should be built into the codes. We probably cannot afford to build everything to Passivhaus standards, but we have to do better than this.