Radiant floor heating is widely recognized for its low-energy consumption and high efficiency. Traditional systems, however, typically heat the entire floor area within a space, conditioning spaces uniformly regardless of occupancy. This study investigates the efficacy of modular radiant floor heating, focusing on part of the floor near the occupied zone versus thermally activating the entire floor area. Utilizing a 62 m3 climatic chamber and a 22-zone thermal manikin we conducted experiments across 6 different scenarios with heated floor areas ranging from 3 m2 to 20 m2, aiming to achieve the same comfort level of the manikin. Mean radiant temperature and radiant temperature asymmetry were measured using novel high-resolution sensors. The results show that smaller heated areas necessitate higher surface temperatures to maintain thermal comfort (e.g., 38 ℃ for 3 m2, and 29 ℃ for 20 m2). The highest radiant asymmetry was observed in scenarios with single-section activation, while lateral asymmetry peaked with two sections, one on the side. Altering the orientation of heated sections while maintaining the same heated surface area resulted in varied thermal environments. Although modular floor heating induced greater radiant asymmetry compared to uniform floor heating, it remained below the threshold for local discomfort, suggesting a viable pathway to improved energy efficiency and occupant-specific thermal comfort. Further investigation of the modular radiant heating performance requires evaluating its energy efficiency and assessing local comfort with real human participants.