In this study, the insulating properties of building materials made out of recycled plant particles were tested with both the laser flash method and the Transient Plane Source (TPS) method. The tests were conducted with aggregates of sunflower pith with particle sizes 1, 1.5, and 2.5 mm, to see how the thermal conductivity behaves with increasing air volume fraction between grains. The TPS method produced values with an increasing trend for thermal conductivity ...