The Science of Building
Let us start by explaining heat. Heat flow can flow in any direction (in or out), though it always flows from hot to cold. When we apply this to buildings, and the basic physics that always applies, heat is transferred in any of three main ways: conduction, convection, or radiation.
Conduction: the flow of heat through solid materials due to a temperature difference across the material. Think of a frying pan. Would you rather pick up a hot cast iron pan or a wood handled one? We all knew the answer to that one when we were 2 or 3 years old. Wood is a better insulator than iron. Insulation is a better insulator than wood.
Convection: occurs when gases and liquids are able to move and carry heat with them. Think of a cold draft on your feet on a winter’s night. Hot air rises and cold air is heavier so it falls. When you have both at the same time it creates a draft.
Radiation: occurs when heat is transferred from one surface to another without contact (conduction) or air movement (convection). An object that possesses more heat energy will radiate the heat through space to an object that is colder as we mentioned above. On a hot summer day would you rather stand in the sunshine or in the shade? The air temperature is the same but the experience of heat is a result of the radiation from the sun.