The Life Cycle of Aluminum Fenestration Products

Operational carbon refers to the greenhouse gas emissions associated with day-to-day energy use during a building’s life cycle (also known as the “use phase”). In the fenestration industry, it is essential because windows and doors directly influence the energy efficiency of buildings. Properly designed and installed fenestration systems can minimize heat loss and gain, thus reducing the need for heating and cooling, which in turn lowers operational carbon emissions. Innovations in glazing technologies and frame materials contribute to enhancing the thermal performance of fenestration products, making them key players in efforts to achieve low-carbon buildings. Products with thermal barrier technologies help to reduce the building energy use, hence the operational carbon. Products such as sun control devices that increase daylighting help to reduce solar heat gain inside the building, which also reduces operational carbon.

Aluminum smelting is the process of extracting aluminum metal from its oxide, alumina, typically through an electrolytic process called the Hall-Héroult process. This process involves dissolving alumina in molten cryolite and then passing an electric current through the solution, separating the aluminum from the oxide. There are four active smelting companies in the U.S. and nine in Canada, as of 2025.

The majority of greenhouse gasses (GHG) from aluminum come from the smelting process. Smelting alumina into aluminum requires varying degrees of energy, but the emissions depend on the power source. Hydropower-driven smelters, like those in Canada or Iceland, can keep emissions below 4 tons of CO2 equivalent (CO2e) per ton of aluminum produced, whereas coal-powered smelters might hit 25 tons CO2e.

This range showcases the impact of energy source on aluminum’s carbon footprint. Smelting paired with clean energy creates a metal that is both eco-friendly and indispensable. The global average emission for primary aluminum production is around 15 tons of carbon per ton of aluminum. The improvements to reducing emission intensity involve switching to cleaner sources of energy.

Carbon anodes used during the smelting process also add some emissions. Carbon anodes release about 1.5 tons of CO2 per ton of aluminum as they are consumed. Innovations like inert anode technology promise to eliminate anode-related CO2 entirely by replacing carbon anodes with carbon free anodes.

From 1990 to 2023, energy intensity fell from 16,000 kWh to 14,000 kWh per ton—a 12.5 percent drop thanks to smarter technology and process tweaks. North America exemplifies this progress, halving its production carbon footprint since 1991 by leaning into hydropower and cleaner grids. With clean energy adoption and cutting-edge technology, aluminum’s environmental impact is shrinking. From fuel-efficient cars to renewable energy infrastructure, aluminum proves that a lower carbon footprint is vital to a cleaner future.

The end of life phase of fenestration products involves their disposal, recycling, or repurposing once they reach the end of their functional lifespan. This aspect is critical in the fenestration industry as it addresses the sustainability and environmental impact of products after use. Strategies for managing the end of life of windows and doors include designing for disassembly, using recyclable materials, and implementing take-back programs. The goal is to minimize waste and maximize the recovery of materials, thereby contributing to a circular economy and reducing the overall environmental impact.

According to the EPA, it is estimated that 90 percent of metal in a building at end of life is recycled. Only 6.9 percent of the 106 billion tons of materials used annually by the global economy come from recycled sources. Aluminum is an exception with its fully recycled properties and thus enables a circular economy.