The current study numerically analyzes Rayleigh-Bénard convection inside an air-laden rectotrapezoidal confinement, where Th and Tc are the invariant temperatures at the lower and the upper wall of the confinement, respectively (Th > Tc). The adiabatic conditions are maintained at the remaining walls. Time-dependent continuity equation, momentum equations and energy equation in dimensionless forms are solved numerically by applying the Boussinesq approximation. Contours of streamlines and isotherms are presented, whereas, the variation of local Nusselt number, Nu along the length of each of the cold wall and the heated wall are also presented for Rayleigh number, Ra = 3.8 × 103, 105 and 106. The average Nusselt numbers at each of the heated underneath wall and the cold top wall are also computed for Ra = 103, 3.8 × 103, 104, 105 and 106. At Ra = 3.8 × 103, the heat transfer is dominated by the mechanism of conduction and at Ra = 105, a convection dominated thermal transport is noted, whereas, in case of Ra = 106, remarkably deformed isotherms are noted with stream function of higher values. The maximum local Nusselt number values at each of the walls with temperatures Th and Tc, respectively, are obtained at different positions for distinct Ra values. With the enhancement in Ra, the maximum Nu and the average Nu, respectively, of each of the isothermal walls enhances. However, when the angle of trapezoidal portion decreases, value of average Nu of the wall with temperature Th decrements.