Long Service Life or Recycling: Which is the Most Sustainable Strategy?

I have had several discussions recently about which is more important – making façade components last longer or creating systems where components can be repeatedly recovered, recycled and renewed. Some assert that façade component lifetime is not that important if this end-of-life recycling and renewal can occur. While this part of the circular economy appears to be an attractive sustainability strategy, it may lull us into a false sense of sustainability.

I have always felt that prioritizing durability and longevity ahead of design for recyclability was the best choice – if there was one to be made – but I could not effectively articulate a clear rationale. That was until I read a paper by a non-profit Danish Design Center (DDC) team and a follow-up commentary by Lloyd Alter. The articles address the criticisms of the circular economy, debunk some myths and add a fourth requirement to the definition of circular economy. They also underscore the primacy of product service life. Keeping materials in service is the highest value in the circular economy.

The linear economy – take, make, use, dispose, waste – requires a lot of energy and raw material depletion.

Circularity is a Lot More Than End-of-Life Recycling

One of the myths the DDC team highlights is that circularity is often seen as only about recycling. In truth, recycling is “one of the last priorities to carry out as a circular strategy for products and materials.”

According to The Ellen MacArthur Foundation, the circular economy or a “closed-loop economy” assumes:

  • Products and materials circulate inside the economy – “using them” rather than “using them up.” This drives a focus on durability, reuse, re-manufacturing and recycling.
  • Waste and pollution are identified and designed out, including greenhouse gas emissions.
  • Nature is regenerated. This means avoidance of non-renewable sources and use of renewable sources.
The circular economy model where materials are shared, repaired, re-used, refurbished, or remanufactured and recycled.

The circular economy aims to replace what the foundation calls the “take-make-waste” linear model of business-as-usual. It notes that the product and material cycle primarily focuses on keeping products in use as long as possible, which emphasizes durability, maintenance and repair and re-use. They underscore that recycling is of lower value because of the energy and cost of remaking products and material loss. Often, recycling becomes a lower value downcycling, too.

Circularity Takes Energy and Resources to Sustain

The circular economy does not come for free. Refurbishment, re-manufacturing, repair and recycling take energy and resources to sustain, especially recycling. Material is lost through each recycle loop, and “virgin” material must be added to maintain the status quo demand. Even more material and energy must be added to sustain a growing market. The fact that material recycling takes significant amounts of energy (cost) is often why recycling isn’t commonly done today.

The DDC notes that “an entirely closed-loop system, even one that recycles, reuses, remanufactures and refurbishes everything, can still result in excessive resource depletion, pollution and waste generation as long as it is driven by growth.” It goes on to state that a fully circular economy is a “physical impossibility” because of the laws of thermodynamics.

The circular economy takes energy and resources to sustain, especially the recycling loop. Recycling is the last choice in the circular economy because of this. Extending service life is a first choice.

We Cannot Recycle Our Way to Sustainability

The DDC team underscores “prevention” as the top priority in the waste hierarchy. Before we design for the 3-Rs (reduce, reuse, recycle), DDC advocates for an additional first R: “Refusal.” This means a refusal to use and a focus on sufficiency. As a result, they have added a fourth item to The Ellen MacArthur Foundation’s definition of a circular economy:

  • “Redefine a meaningful life with less consumption.”

DDC says, “Often, the circular choice means not buying something new – holding on to products for a more extended period, taking better care of products and materials, repairing and sharing instead of owning.”

In his follow-up commentary, Alter concludes, “The way to build a circular economy is to use less stuff.”

Recognizing “sufficiency” or “enoughness” as a key sustainability strategy is growing. It is supported by Kate Raworth’s Doughnut Economics model, which describes a safe and just space for sustainable economic growth. This model is based on a foundation of social equity, peace and justice, with a ceiling limiting growth to that which does not irreversibly damage the Earth’s ecological systems.

The Doughnut Economic model by Kate Raworth. Credit: Figure by Technoform from Kate Raworth’s model.

Implications for Building and Façade Systems

What does this mean for building and façade systems?

  • Designing for longevity trumps recyclability – if there is a choice to be made. Ideally, we would achieve long-lived, maintainable, upgradable fenestration and insulating glass systems AND design them to be de-constructible and recyclable at the end of their life. We would also establish an effective reclamation infrastructure to close the circular loop efficiently. But the hierarchy of importance seems clear: Think durability before recycling. Doing so automatically helps us to use less stuff over the long term.
  • Using less stuff: In many cases, using less stuff is correlated with reducing embodied carbon emissions. The choice to build or not is the main driver of embodied carbon (and using less stuff). Thereafter, and as I have written previously, embodied carbon reduction continues to be driven by design choices, most of which are also driven by using less stuff:
    • to renovate rather than build new
    • the size of a new building (how big is big enough?)
    • the amount and type of insulation
    • the choice of a single versus double façade
    • the thickness and number of panes in the insulating glass units (IGUs)
    • to design with fewer unique and more efficient IGU sizes, which conserves material because it results in less waste during fabrication

Making more energy-efficient façades often results in using more stuff, such as triple-pane glazing, additional insulation and double-skin façade systems. A balance exists between long-term operational efficiency (which influences operational carbon), occupant comfort and resilience, and upfront investment in embodied carbon. Using more stuff upfront may be the right choice for resilience, occupant comfort and cumulative carbon emissions, but this hinges on the first choice: Do we need to build new? Can a current space be refurbished rather than demolished and rebuilt?

Jurisdictions are already starting to wrestle with “to build or not to build.” In the United Kingdom, the London City Council recently denied a planning application from a leading British retailer to demolish its flagship store on Oxford Street and redevelop the site, questioning the need to build new because of concerns for embodied carbon.

Recycling is Important but Not Sufficient

Notwithstanding the focus on extending service life, we must also pursue efforts to recycle glass and other carbon-intensive façade materials at the end of life. The glass industry has started to work on creating glass recycling programs. These programs not only have the potential to prevent value-reducing downcycling into insulation and road construction materials (and worse, disposal to landfill), but they also increase recycled material in the float glass process, which reduces the energy (and carbon) needed to make it, by reducing the melting temperature.

Bertrand Cazes, Glass for Europe’s secretary general, said that a 2-3% reduction in energy consumption could be achieved for every 10% recycled glass cullet used in the batch. It also reduces the impact of raw material extraction—a triple benefit.

Recycling building glass is a good thing. However, in general, recycling cannot be used as a synonym for the fenestration circular economy due to all the abovementioned reasons. Recycling alone is insufficient. For a truly circular economy, our efforts must be broader, focusing on sufficiency, service life extension, maintenance, re-use, re-manufacturing and designing waste and pollution out of the process.

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