To know the three basic methods of heat transmission and how they will flow through walls, floors, ceilings, windows and doors. Heat seeks a balance with surrounding areas. When the inside temperature is controlled for human comfort, there will be some movement of heat. Heat moves from the inside to the outside during the winter and from the outside to the inside during the hot summer weather. For heat transfer to occur between two mediums, one medium must contain more heat.
Heat always moves from the warmer medium to the cooler medium.
Heat is also transferred at a rate directly related to the difference in temperature, and the resistance to heat flow provided by the materials between the two mediums. Dense materials like metal or glass conduct heat more rapidly than porous materials like wood or fiber products. Any material will conduct some heat when a temperature difference exists. Convection - Convective heat travels through a fluid. As the warmer molecules rise, the cooler ones sink to create convection currents.