Modelling and measurements of heat transfer coefficient in classroom experiments

Thermal insulation of buildings is important because it has both ecological and social impacts. Most often, it is characterized by the so-called U-value. Heat transfer through walls includes conduction, convection, and thermal radiation. This leads to complex measurements and calculations for assessing the effectiveness of different insulating materials, and the usual methods are not suitable for classroom experiments. We propose a simple method for measuring the U-values of varied materials used in everyday life that can be performed in the classroom. It is based on measuring the temperature inside and outside a box, and the power, released by a resistance coil inside the box.