Case Study – Large City Building Model: Upgrading Glass from Single to Multiple Pane Using an Interior Window Retrofit

Retrofit glass technology, in which a secondary glass panel is installed behind existing single glazed glass windows, is a small building upgrade that can provide significant energy saving results: commercial buildings can save over 20% of their building’s energy consumption with retrofit glass technology.

Thermolite created a building model study to show how our RetroWAL™ Silver Series interior retrofit window system would impact energy savings in large city commercial buildings with non-thermally broken, single glazed curtain wall, taking into account:

• Existing window U Values
• Solar Heat Gain Coefficients (SHGC)
• Air infiltrations

Thermolite then applied this calibrated building base model to buildings in large cities throughout the US in order to determine what areas of country would benefit the most from our RetroWAL™ Silver Series window retrofit. Climate was found to be the most significant factor in energy performance improvements with retrofit glass technology.

• The average reduction in total building energy in the 10 city analysis was 23%.
• ROI is approximately 6 years in cold climates and upwards to 28 years in warmer climates in single to double applications.
• Single to triple applications significantly decrease the ROI in warm climates to 16 years, while remaining stable for cold climates at 7 years for ROI.

View the full case study for complete details. 

The Thermolite engineering staff is an innovative structural, energy modelling, and implementation team that works to create unique window systems alternatives to traditional replacement windows. Our systems protect against blasts, hurricanes, and sound, while being energy efficient and quick and easy to install. We serve a wide range of industry buildings including government, military, historical, schools and universities, financial, health care, hospitality, and offices. Contact us today to learn how we could update your building’s window systems