Detecting and quantifying refrigerant leakages in residential heat pumps (HPs) at an early stage is a major stake to maintain their efficiency and extend their lifespan. It is also of great interest in terms of safety when using flammable refrigerants. Research aimed at developing methods for detecting leaks or quantifying the refrigerant charge is abundant. The state of the art conducted as part of this thesis identified the limitations of existing methods: they are not accurate enough, too specific to a given system, not suited for in-situ implementation, or addressed systems equipped with basic and obsolete control devices. Moreover, most research has focused on air conditioning or cooling systems, and very little on HPs in heating mode. The thesis presented here therefore aimed to deve ...