In this study, the effect of wall orientation on the optimum insulation position in the wall from different perspectives is studied numerically. Using Crank- Nicolson One dimensional transient heat conduction equation is solved for the wall with convection boundary conditions. Outdoor temperature is considered as a periodic function of time. Since natural night ventilation is used in the building, indoor temperature is constant during day time while air conditioning (AC) system is ON and is time dependent when AC is OFF. A time dependent indoor temperature is calculated and used as a boundary condition at the wall inner side. For the position of insulation in the wall six practical configurations are considered and time lag (TL), decrement factor (DF) and total conduction heat gain (TCHG) is calculated for all configurations. It is seen that, from minimum TCHG perspective, the best configuration for all directions is when insulation is used in the inner side of the wall. The minimum TCHG is occurred at an angle of 200⁰ from the south. It can be concluded that different perspectives may lead to different results for the optimum insulation position in the wall.