How exactly does the warm edge benefit the window?

Ensinger, manufacturer of Thermix® warm edge spacers recently launched a new app version of its Uw calculator to determine the thermal transmission coefficient of windows. The app is available in both an android and iOS version or online at

Ensinger is exhibiting:

Fenestration Bau China
05.11. – 08.11.2019
Shanghai, China

With the Uw app from Ensinger, users can calculate the thermal transmission coefficient of windows in compliance with EN ISO 10077-1. The ψ (in other words Psi) values of Thermix® spacers taken into account in the calculation are based on representative frame profiles and glazing in compliance with the Data sheet of the German Flat Glass Association (within the scope of validity of Guideline WA-08/2 of the Institute of Window Technology (ift)).

„In just a few moments it is possible to tell how good a window actually is from the thermal insulation point of view“, explains Wincent Wei, Business Manager for Thermix® and insulbar® at the plastics specialist Ensinger. „To date, people have simply managed using table values, although the results were often poorer and less precise. Using this app, architects, planners and window manufacturers can calculate the Uw value both quickly and correctly. This is a really useful aid, particularly when dealing with more complex windows, such as those with bars.“

The first thing to do when using the app is to select the calculation basis, then the required frame material and frame width. There are a variety of frame types stored in the system: Wood, PVC, aluminium and wood-aluminium. The next stage is to choose the spacers, the glass and window geometry. Double and triple glazed window units can be calculated. The information can then be supplemented by the number of sashes, the temperature range and the type and orientation of bars.

The ψ values of the spacers are also included in the calculation, as are facts about the muntin bars. After performing the calculation, a PDF document can be created for saving or printing out. The configured system is also graphically displayed. The app is available in 13 language versions, also in Chinese.

Picture 1: With Thermix® WinUw, window constructors, energy advisers, planners and architects can easily calculate the thermal transmission coefficient (UW) of a window in order to optimise the configuration with respect to the energy efficiency.

Pictures 2 & 3: Thermix® spacers from Ensinger increase energy efficiency through better thermal separation in the edge zone of insulating glazing.

The Thermix® Uw calculator is available free as an app in 13 languages, the iOS version from the Apple Store and the android version from the Google Play Store.