In Nigeria, the total wood removals from forests in 2005 amounted to 86,626,797 m3. The amount of fuel wood consumed from forests in the year 2005 was 72,710,935 m3. As at 2018, emissions from Nigeria's kitchens contributed to about 55 million tons of CO2. A huge amount of these emissions are from large scale cooking in our boarding secondary schools, commercial restaurants and large households. The traditional three stone stoves being used in these quarters are inefficient; hence, the need for developmental research works on Improved Cooking Stoves (ICS). Towards the direction, a lot of ICS have been developed; however, there is still some knowledge gaps that need to be filled in the areas of combustion and thermal efficiencies. This work presents the comparative thermal and exergy efficiency analysis single and cascaded three pot firewood energy saving stoves. The 50cm diameter pot stoves were constructed using 2mm thick steel metal with inner linings filled with ash as insulating material. The cook stoves were tested using standard water boiling and cooking test methods. It was shown from the analaysis of the result that; the single pot and cascaded-pot rocket stove were estimated to have thermal efficiencies of 28.7, 42.45%, and 43.55%, respectively. The Specific Fuel Consumptions (SFC) for the respective stoves was 0.31, 0.21 and 0.19. The Specific Time Spent (STS) in cooking were 8.43, 6.9 and5.9 respectively. A single-pot and cascaded - pot cook stove can save about 27,231.4 and 40,847.1 toe/ capita of fuel wood per annum, respectively. The result shows that Carbon emissions of single and cascaded cook stove are estimated to be reduced by about 1886kg and1990 kg per annum respectively.