We plan to develop and make use of novel out-of-equilibrium spectroscopy techniques that give access to energy transfers inelectronic nanocircuits. The unveiled information will be used to investigate promising quantum phenomena and to explore newroutes to control the mechanisms that limit their potentialities for nanoelectronics.The proposals backbone is the spectroscopy of the fundamental electronic states energy distribution function f(E) that wedemonstrated this fall 2009: by using a quantum dot as an energy filter, we performed the first measurement of a non-equilibriumf(E) in a semiconductor nanocircuit. We plan not only to employ it, but also to develop complementary techniques which will furtherwiden our range of investigation. We anticipate this f(E) toolbox will be crucial for the rising field of out-of-equilibrium mesoscopicphysics.We will first examine through the unexplored facet of heat transport the quantum Hall effect regimes, which exhibit a large varietyof puzzling many-body quantum phenomena and are of particular interest for their metrology applications and quantum informationpotentialities. The planed experiments will be done for various out-of-equilibrium situations, which will permit us to address longstandingopen questions, such as the nature of pertinent excitations, and to test original ways to increase quantum effects.We will also perform direct energy exchange measurements to investigate the inelastic mechanisms that set the length and energyscales of coherent and out-of-equilibrium physics in nanocircuits. The novel f(E) spectroscopy will permit us to take advantage ofthe two-dimensional electron gas circuits high modularity to study many transport regimes and geometries that remain unexploredfrom this revealing viewpoint.