The document discusses three main factors that affect body heat loss: temperature, air movement, and relative humidity. It then discusses the types of body heat loss: radiation, convection, and evaporation. The document promotes a radiant heating system called Therma-Ray that provides efficient, consistent heating throughout a room from floor to ceiling. It claims Therma-Ray is more economical to operate than other heating systems like oil, gas, or electric forced air. Installation costs and estimated operating costs are provided for Therma-Ray in different home sizes.