Conduction, Convection and Radiation are the three ways that heat is transferred.
What is conduction heat?
When two surfaces come in contact, the warmer surface gives up heat to the cooler surface as can be seen with a glowing burner on a stove heating the pot it is in contact with. In a building this is limited primarily to studs connecting outer and inner surfaces.
What is convection heat?
The movement of air as a result of air being warmed. Warm air rises seeking the coldest point. Convection is visible as wavy lines above a hot road. Convection is a major concern in the winter, but not in the summer.
What is radiant heat?
Radiant heat travels in all directions striking cooler objects and transfer the heat. This infrared energy is like microwave ovens at a lower frequency. We may not understand infrared radiation but we can learn to make it work for us by learning how to control it and make it work for us.