Over the past few months, I’ve been noticing more jargon floating around the industry referencing “life cycle analysis” (LCA). Now a different definition of the phrase is sneaking in, and it’s something that bears watching as it’s related to energy and what’s going on with curtainwalls and windows from a project cost perspective.
It’s been my experience that “life cycle COST analysis” is a pretty common phrase, referring to how much a product costs – in this case for curtainwalls and windows – over its life in a building. That’s generally been limited to how much it costs to install, maintain, operate and eventually replace any component. But the life cycle analysis currently being discussed in the building industry is not a cost analysis.
This new definition deals primarily with how much energy it takes to produce and operate the windows, from mining the raw materials to manufacturing to installation to operation and maintenance. For aluminum, the analysis would take into account the mining of the raw material, its refinement into usable aluminum billets, extruding it, then the fabrication into window components, and ultimately the energy costs associated with the operation once installed on site. Transportation costs between any two of these operations are also tabulated into the analysis.
Some people are calling this a “cradle to grave” analysis, as it takes into account every energy watt and BTU that goes into the ENTIRE life cycle of a product. “Embedded energy” is another term that’s being used. The LCA basically combines all energy factors over the entire life of a product.
Obviously, within a glazed system – be it aluminum, steel (I have to include steel, it’s what I do for a living, right?), or other material – the glass and framing are the easiest components for which to determine the LCAs. But for smaller components such as finishes, fasteners, gaskets and sealants, it’s not known yet how these or the myriad other products that go into the windows will figure into the final LCA.
The University of Minnesota’s Center for Sustainable Building Research was trying to take the lead to develop LCAs for windows and curtainwalls, but has recently tabled their efforts due to funding issues. Two of our favorite groups, the NFRC and DOE, are trying to get LCA data for window and curtainwall products.
What’s the eventual use of data like this? With the emphasis being on green products, this could be a more holistic view of the actual energy of a given product over its entire life, not just how much energy it takes to operate it once it’s installed.
This is going to be an oversimplification, maybe, but if a wood framing system were found to have a lower LCA than a comparable steel or aluminum system, it might give the project designers another tool to use in selecting products. Whether it can perform as well as the steel (not likely in a hurricane zone) is a different criteria, but the LCAs are going to go into the mix, right along side the other issues, such as performance, aesthetics, availability and costs – to add one more layer of decision / criteria the designers get to select.
This comparison of what we now think of curtainwalls may go much deeper. A recent presentation by a pretty well known architectural firm compared a punched opening window in a precast wall panel to an aluminum curtainwall, and found the precast/punched window required a lot less energy to produce from cradle to grave. Due to results like this, that architectural firm might move away from a conventional aluminum curtainwall system and go to something that requires a lot less energy to produce AND run.
In that scenario, it’s easy to see that other technologies being developed may come to the fore. Recently, Graham Windows presented a new framing product that eliminates aluminum extrusions and replaces it with glass strand reinforced profiles, which may require less energy to produce than aluminum extrusions. At TGP, we have a large focus on steel framing systems: steel has a lot lower embedded energy than aluminum, and we get calls from architects because of it. Steel has other values in overall energy performance, as well. Not to beat TGP’s own drum, but the energy-conscience designers out there are looking at issues like this to get to as low an energy impact as possible. Not tomorrow, which would be great, but downright soon!
The issues of “how much energy is in the raw material” along with “how much does it take to operate it” are starting to creep into the industry, and in the space of who knows how many years, this may all change. Who knows? Like they say, the only thing that doesn’t change is that things change… If I had a crystal ball, I’d sell insurance.