The relevance of radiant space cooling system over conventional Variable Air Volume (VAV) space cooling system with reference to economics, system operation, installed capacity, energy consumption, and human thermal comfort has been studied for commercial office buildings in India. EnergyPlus energy simulation program has been used to evaluate radiant and VAV space cooling system performance for energy conservation building code (ECBC) compliant commercial office buildings in four climate zones of India. The study incorporates the Life Cycle Cost (LCC)approach to compare the economic benefits of radiant and conventional VAV cooling systems. LCC provides a better long term cost assessment of a project alternative over its complete life cycle, including initial capital costs, maintenance costs, operating costs and cost or benefit of eventual disposal, than other economic methods that focus only on first costs. With acute peak load deficit and load shedding prevalent in many parts of India, this paper also compares the impact of the radiant and VAV space cooling systems on human thermal comfort during the grid power outage period. This aspect is important to study for the office buildings in India where cooling system is either shut down or switched to diesel generator-power during short-term unavailability of power from the grid.