What is Heat Bridge? What is the contribution to insulation ? How to prevent heat losses? Heat transfer is from the high-energy (hot) side to the low-energy (cold) side. Therefore, cold room insulation is designed and realized in such a way that heat from outside does not enter, not to prevent the cold inside to escape. Heat transfer is defined as the transfer of energy between two or more objects with different temperatures, by conduction, convection or radiation (or by combining these paths with each other). Convective heat transfer is mainly due to the mass movement of molecules. Fluid in motion between two different temperature surfaces provides heat transfer during this movement .