Building and transportation sectors account for approximately 75% of CO2 emissions. A mitigation strategy that combines both renewable energy sources and adoption of all-electric vehicles (EVs) instead of conventional gasoline powered vehicles thus seems most promising. The desired outcome of this strategy cannot be achieved without taking into consideration human activities in building and transportation. This study compares the energy use in building and transportation, aiming to provide a proper approach for evaluating the effectiveness and possible CO2 emissions reductions of GHG mitigation strategies. The analysis of the collected data showed that on average each individual produced around 20lbs of CO2 per day, 62% of the total CO2 was emitted in transportation. The mitigation strategy including EVs powered by electricity generated from coal-fired power plants resulted in average CO2 emissions reductions of 3.7%. The mitigation strategy using the EVs powered by solar energy obtained from grid-tied solar panels have led to 12.2% CO2 emissions reductions per day (from 12.38lbs/day to 10.87lbs/day), and the strategy incorporating EVs with the off-grid source of power was the most successful strategy and resulted in an average CO2 emissions savings of 12.38lbs/day. This study also estimates the initial cost per pound of CO2 emissions reduction per day for each of the mitigation strategies.