Improving Building Envelopes

Sustainable buildings require good walls, windows, and roofs—their “envelope.” Air sealing and insulation are prerequisites for energy savings and resiliency in both new projects and retrofits. The choice of façade material and window design will drive a building’s sustainability profile for a generation or more.

The envelope is arguably the biggest driver of a building’s overall sustainability, and seemingly basic techniques, like air sealing and insulation, can make a huge impact in new projects and retrofits. The choice of façade material and window design will drive a building’s sustainability profile for a generation or more—and play a major role in habitability during extreme weather. Through our efforts, NYC now has laws that minimize air leakage through building exteriors and encourage increased external insulation and super-insulated exterior walls.

Our latest report, Spending Through the Roof, found that vents once required to remain open in elevator shafts leak enough heated air to fill the Empire State Building 29,000 times over, and provides step-by-step instructions on how to calculate potential savings and fix the problem.

 

 

In last year’s High Cholesterol Buildings report we found that modern buildings often favor souped-up internal systems over efficient envelopes. While this can result in a property that looks good on paper, over time that façade will become a barrier to sustainability. In fact, you’d have to go back over 1,000 years to find buildings that used as little insulation as some of today’s structures.

 

Our 90 by 50 report again stressed the importance of air sealing and insulation for NYC to reduce its carbon footprint 90 percent by 2050—and to hit Mayor de Blasio’s 80 by 50 goal.

 

 

 

Following Superstorm Sandy in 2012, we were compelled to look at how different building envelopes would fare during an extended power outage during extreme heat or cold. Baby It’s Cold Inside unfortunately showed that most buildings would not do well at all, becoming dangerously hot or cold after just a few days.

 

 

In 2011, There Are Holes in Our Walls found that the average room air conditioner leaks as much air as a six-inch-square hole.

 

 

 

We first looked closely at building envelopes when we released the Green Codes Task Force Report in 2010.