Hotbox Test Chambers
Determining the stationary heat transfer properties of complex components and finished products used in construction such as doors, windows and bricks
In a world increasingly focusing on sustainability, energy efficiency, and safety, accurate knowledge of the heat transfer properties of building materials is crucial. Whether it's about the insulation of buildings, the efficiency of windows and doors, or the overall energy balance of facades, precise determination of these properties is essential. This is where the innovative Hotbox test chambers come into play – the ultimate solution for measuring and analyzing the heat transfer properties of wall elements, walls, windows and doors.
Our Hotboxes: TDW Series
Explore the range of NETZSCH TDW instruments
About the Hotbox Method
Hotbox Test Chamber - How does it work?
In a hotbox, real-world conditions as they would exist for a building wall are simulated: In practice, both conditions inside the building and on the outside can be simulated. This means that temperature, humidity, air speed and radiation properties on both sides of the test wall must be detectable and precisely adjustable.
There are usually two test chambers (warm and cold section). Between them is a test frame with the sample positioned. Stone walls to be tested are first bricked onto a base and then dried in drying chambers. Windows, doors or facade parts are mounted directly on the test frame. The prepared test frame is inserted between the warm and the cold section to be measured.
In NETZSCH Hotbox systems, homogenity of the flow and temperature profiles is achieved to be in accordance with international standards like DIN EN 1934, DIN EN ISO 8990, DIN EN 1946-4, DIN EN ISO 12567, DIN EN 12412-2 and ASTM C1363. This means that the same temperature and air speed must prevail on the test wall at every point of the warm and cold sections.
What Purpose Do Hotbox Tests Serve?
The heat transfer through a brick wall or a window part is defined by the U-value: The lower the U-value, the lower the lost heat-flow and the better the insulation properties of the building part. The U-value is therefore a measure of the energy efficiency of parts of a building envelope such as brickwork, facades, windows and doors. Manufacturers have to specify the U-value of their products.
We offer two different Hotbox systems: The TDW 4040 with a Heat Flow Meter and the TDW 4240 with a controlled Hotbox.
Frequently Asked Questions
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What Makes NETZSCH Hotbox Testing Chambers Unique?
- Wide Specimen Accommodation and Tailored Solutions for Various Applications:
NETZSCH systems are designed to handle diverse testing scenarios with flexibility in specimen size and thickness, making them ideal for a wide range of materials and applications.- TDW 4040: For compact brickwork and materials, accommodating specimens up to 1500 mm x 1500 mm with different thicknesses.
- TDW 4240: For larger building components like windows, doors, and profiles
- Advanced Software Integration: The Hotbox Software simplifies testing with easy parameter selection, real-time data acquisition and automated, comprehensive report generation. This allows for reproducibility and saves time compared to less intuitive systems.
- Customization Options: Optional features, like adjustable humidity levels, allow the simulation of real-world conditions, improving the accuracy of test results. Take advantage of our level of flexibility in environmental simulation.
- Market Reputation and Proven Excellence: NETZSCH is a trusted leader in thermal analysis, rheology and fire testing with decades of experience. Benefit from our durable, high-performance systems, reliable after-sales support, including maintenance, calibration and training. This ensures peace of mind for long-term use.
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Hotbox Applications
The NETZSCH TDW 4040 and TDW 4240 systems are advanced HotBox testing chambers designed for precise thermal performance analysis of construction materials and components. By simulating real-world conditions, they deliver accurate evaluations of Thermal ConductivityThermal 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 and U-values, making them indispensable tools in the construction and building materials industry. These systems support diverse applications, including energy-efficient building designs, material optimization, and regulatory compliance, ensuring high-quality results under realistic testing environments:
- Building Insulation Materials
These systems are ideal for testing the Thermal ConductivityThermal 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 and insulation performance of materials such as bricks, concrete, lime sand bricks, aerated concrete, and composite materials. This helps manufacturers optimize material properties for energy-efficient construction. - Windows, Doors, and Facades
The TDW 4240 is specifically designed for analyzing the thermal behavior of larger components like windows, doors, facade systems, and structural profiles. This is critical for meeting energy efficiency regulations and enhancing sustainable building designs. - Rehabilitation and Retrofitting Projects
They are valuable tools for evaluating the thermal properties of materials and components used in retrofitting projects, including the addition of insulating layers to existing structures or testing new designs for older buildings. - Research and Development in Sustainable Materials
The systems aid in the R&D of innovative, eco-friendly materials, such as recycled composites or bio-based insulations, helping manufacturers achieve sustainability goals while maintaining high performance. - Regulatory and Standards Testing
By adhering to international standards like DIN EN ISO 8990, ASTM C1363, and DIN EN 1934, these systems support manufacturers, testing laboratories, and research institutes in certifying materials and products for market compliance.
NRG-STORAGE PROJECT*: Let’s push the boundaries of energy-efficient construction!
Our latest study from March 2025 presents the first systematic evaluation of NRG-Foam, a patented cementitious insulation material designed to balance thermal insulation and heat storage while maintaining mechanical integrity. We compared NRG-Foam-insulated walls with standard expanded polystyrene (EPS) panels, assessing their thermal performance under standard static conditions as well as dynamic real conditions in a NETZSCH Hotbox!
By participating in the EU-funded NRG-STORAGE project, NETZSCH is actively contributing to the EU’s target of becoming carbon-neutral by the year 2050.
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