SOLVED: HVAC Psychrometric: How do I prove from a psychrometric chart that when temperature increases, the humidity will decrease? For example, let's consider a room with no heat load at 22°C and 70% relative humidity (RH). Now, if I want to increase the supply temperature to 24°C, the RH will supposedly drop. But how can I prove this using a psychrometric chart? I need to present and prove this in a simple way so that people with no technical knowledge can understand.