Steven's Power Law
Steven's Power Law is a psychophysical concept that states the the strength of a physical stimulus is proportional to the sensation that is perceived by the recipient. The magnitude of the sensation increases in a predictable and proportional manner to the strength of the stimulus. This can be measured using a variety of stimuli including light brightness, auditory volume, vibration, temperature, taste, and smell.
Steven's Power Law essentially states that as a stimulus increases in magnitude (a room growing increasingly warmer) it will increase the sensation of the stimulus proportionally (you're not cold any more, you're getting a little warm and remove a sweater, you start sweating and growing uncomfortable).