This chapter explores the physics of Ohmic contacts (OCs) within the quantum Hall regime, focusing on their role in charge and heat transport in mesoscopic systems. The OC is modeled as a floating metallic reservoir interacting with quantum Hall edge channels, leading to significant charge and energy fluctuations. By analyzing the system’s charge and heat dynamics, we derive the specific heat, energy relaxation times, and key noise properties of the OC. The framework incorporates bosonic field theory and Langevin equations to describe charge conservation and thermal fluctuations, ultimately leading to an explicit relation between charge and heat currents. We further investigate the heat Coulomb blockade effect, where charge quantization and finite capacitance limit heat equilibration. Extending the analysis to multiple edge channels, we demonstrate how the OC modifies energy transport and affects heat conductance quantization. These insights are crucial for understanding the mechanisms of dissipation and energy distribution in low-dimensional electron systems, with implications for quantum thermodynamics and electronic cooling in mesoscopic devices.