The term "more heat-on" implies an increase in temperature or intensity. On the other hand, antonyms for this phrase may include "less heat-on" which suggests a decrease in temperature or intensity. Other antonyms could be "cool down" or "calm down," which indicates a reduction in stress, tension, or energy. "Peaceful" or "tranquil" could also indicate a state of rest, relaxation, and low-intensity, which would be the opposite of "more heat-on." These antonyms can be applied to various settings, from physical environments such as a cooling room or a serene garden, or to emotional or mental states where one seeks to disengage or find inner peace.