The document discusses the different stages of heating throughout history and their effects on the environment. It begins with early humans discovering fire over 1.6 million years ago, which allowed for cooking and lowered disease rates but also caused pollution. Later stages included the use of fireplaces in ancient Rome and improvements over time. Other methods discussed are electric blankets, hot water bottles, and underfloor heating originating in ancient China. Modern underfloor heating uses electric or fluid-based systems. Overall, heating has impacted both the environment and human life in both positive and negative ways.