Plastic waste is a major environmental and scientific challenge of our century. The current paradigm of "waste management" must evolve towards "resource management" by identifying a highly sustainable material consuming sector. The general objective of this paper is to propose a simple, economical and efficient solution for the recovery of plastic waste for the building sector. We have experimentally evaluated the performance of a Loose-Fill Plastic Waste (LFPW) as a thermal insulation solution. For this purpose, a literature review was conducted to guide the design and conduct of an experimental study on test cells in the cold and humid climate of Reunion Island (France). Our literature review shows that this form of plastic waste recovery is a world first. The LFPW reduces surface temperatures by nearly 5.4 °C, with a maximum difference of nearly 16.5 °C. The thermal phase shift is also remarkable (between 70 and 150 minutes). This technical solution makes it possible to achieve performances comparable to conventional thermal insulation solutions while combining circularity and technological development. It is a realistic opportunity for emerging countries.