If high-performance glazing was installed in all buildings in the European Union, it would have the potential to deliver up to 75.5 Mtoe* of energy savings in 2030 according to the “Glazing Potential: Energy Savings & CO2 Emission Reduction” report by Dutch-based independent research institute TNO Built Environment and Geosciences, commissioned by Glass for Europe.

The report analyzes two scenarios: all windows being replaced in 2030 with readily available high-performance glazing and all windows being replaced in 2050 with improved high-performance glazing. The total annual energy savings is 75.5 Mtoe in 2030, or a 29% reduction in buildings’ energy consumption, and 67.3 Mtoe in 2050, or a 37% reduction in buildings’ energy consumption. This results in a total annual CO2 emission savings of 94.3 MtCO2** and 68.5 MtCO2, respectively.

According to the report, the massive potential can be attributed to the fact that Europe’s current buildings are mostly equipped with dated, inefficient glazing.

“Glazing can now be selected to offer the best energy balance between thermal insulation properties (Uw value) and ability to capture or repeal solar heat gains (g value). With the adequate type of glazing, energy savings are maximized in all building types and under all climatic conditions,” reads the report.

Past glazing systems such as single glazing and double uncoated or early glazing have Uw-values of 5.8 and 2.8, respectively, according to Glass for Europe. The average performance of EU building stock is a Uw-value of 3.4. This is much higher than today’s high-performance glazing systems. Insulating double glazing has a Uw-value of 1.4 and insulating triple glazing has a Uw-value of 0.9.

The report concludes that nearly half of the maximum saving potential identified for 2030 could be realized in ten years by doubling the window renovation rate with high-performance glazing.

The current window replacement rate across Europe is approximately 2%. Doubling the renovation rate would bring it to 4% per year and the worst performing windows would be prioritized for replacement.

“For this potential to materialize, more renovation must go hand in hand with the installation of glazing whose performance are optimized for building types and locations,” reads the report.

Using high-performance glazing can also mitigate the need for cooling in buildings. Adequately using high-performance solar-control glazing could result in a 27% reduction in energy consumption used to cool buildings all across Europe in 2050, according to the findings. The report points out that the installation of cooling equipment in Europe’s buildings is expected to increase dramatically by 2050 in both residential and commercial buildings. High-performance solar-control glass increases comfort and minimizes the heat load and need of air-conditioning, something the report recommends taking into account when replacing windows.

“What is most outstanding is that because windows stay on buildings for decades, the amount of CO2 avoided over several years grows exponentially. For instance, between 2020 and 2030, a doubling of window renovation rates would avoid the release of above 240 million tonnes of CO2. This is more CO2 saved than was emitted in 2016 by all the Baltic States, Finland, Sweden and Denmark together,” reads the report.

Policy Recommendations

The report includes several policy recommendations intended to achieve the massive potential for energy savings and CO2 avoidance thanks to high-performance glazing. The recommendations include:

  • Actions to moderate buildings’ energy consumption to achieve CO2 emission savings;
  • Taking actions to save energy today rather than later;
  • Increasing the building renovation rate; and
  • Creating policy actions that steer markets toward high-performance glazing.

*Mtoe stands for million tonnes of oil equivalent. A tonne of oil equivalent is equal to the amount of energy released by burning one tonne of crude oil, according to the University of Calgary.

**MtCO2 is metric tons of carbon dioxide equivalent.