Recently, dynamic cool roof (DCR), with the ability to reduce its solar reflectance during heating period, is introduced as a proper replacement for traditional cool roof. Another ideal roof solution is green roof (GR), which can reduce both heating and cooling loads of a building. This study aims to compare air-conditioning energy demands of a residential building with DCRs and GRs, based on numerical analysis with EnergyPlus. Different climatic conditions, thermal mass and insulation levels were considered in the simulation. Also, in order to assure the validity of the results, optimal properties for GRs and the best strategy for switching coatings of DCRs were found before the comparison analysis. The results show that for hot and humid climate, GRs with regular irrigation system are the best roof technique, which can reduce annual thermal loads of the reference building with conventional concrete roof by 17.8–171.4 kWh/m2 (21.3–66.0%), depending on thermal mass and insulation levels. In hot summer-cold winter city, DCRs outperform both dry and wet GRs with the potential to decrease annual energy demand by 11.8–66.7 kWh/m2 (22.4–35.4%). While in area where space heating dominates, dry GRs have the best energy performance, as they can save annual energy of the reference building by 5.5–124.0 kWh/m2 (6.9–44.1%). Applying these optimal roof techniques can reduce annual CO2 emissions of the reference building by up to 20.2–34.5 kg/m2 (38.3–56.6%), depending on the region.