This paper presents an energy efficient 1-bit full adder designed with a low voltage and high performance internal logic cells which leads to have abridged Power Delay Product (PDP). The customized XNOR and XOR gates, a necessary entity, are also presented. The simulations for the designed circuits performed in cadence virtuoso tool with 45-nm CMOS technology at a supply voltage of 0.9 Volts. The proposed 1-bit adder cell is compared with various trendy adders based on speed, power consumption and energy (PDP). The proposed adder schemes with modified internal entity cells achieve significant savings in terms of delay and energy consumption and which are more than 77% and 40.47% respectively when compared with conventional “C-CMOS” 1-bit full adder and other counter parts.