16.03.2020 by Milena Riedl

Thermal Conductivity of Insulating Glass Windows and Skylights

Building regulations in various countries require minimum Conduttività TermicaThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.thermal conductivity (U-values) for different parts of a new building. This refers to anything from external walls, floors, roofs, windows and doors. Guarded Hot Plates (GHPs) determine these important values. Read here how!

Building regulations in various countries require minimum thermal conductivity (U-values) for different parts of a new building. This refers to anything from external walls, floors, roofs, windows and doors.   U-values measure how well a window prevents heat from passing through it. This will be what dictates how much heat is let into a home during the summer and how much heat is kept in during the winter. The reason why this is important is the lower the U-value, the less heat loss the window is going to allow. Having a low U-value on windows will make a home much more thermally efficient.   U-values are measured in watts per square meter per Kelvin or shortened to [W/(m²×K)].

GHP 900 S in accordance with important industry standards

Manufacturers determine the thermal conductivity and the U-value of windows and skylights with guarded hot plates. These are cabinet devices with a tiltable test chamber, which are especially suited for thicker specimens and insulating glass. The U-value of an insulation glass window depends on the mounting angle (vertical, horizontal or in between) due to different heat transfer conditions within the gas phase. The GHP 900 S is able to measure the thermal conductivity of insulation glass windows depending on temperature and mounting angle.   The GHP 900 S by TAURUS NETZSCH Instruments measures specimens in accordance with several important industry standards like ISO 8302, ASTM C177, EN 1946-2, EN 12664, EN 12667, EN 12939 and EN 674.

Figure 2: GHP 900 S by NETZSCH TAURUS Instruments

The data logging and control of the device is done via the external desktop device Lambda Control and a PC with Windows operating system and Lambda software.

The Lambda Software

The intuitive software allows for simple data acquisition and evaluation of measurement results. It is possible to choose between a manual or automatic measuring procedures making it easy for any operator to use the software. The software displays all relevant data, measuring results, intermediate and final results in graphs and tables. Test reports can be customized.

Figure 2: Lambda software

Learn more about the possibilities of measuring the thermal conductivity and U-values of insulating glass and other building materials in our brochure.  Visit our website to learn more about our product portfolio!