Type of heat is a broad term that can refer to many different forms of energy transfer. BASEBOARD heat, with nine letters, is a type of heating system that uses convection to transfer heat from hot water or electric coils through metal or plastic pipes located in the walls or baseboards of a room. RADIANT heat, with seven letters, is a type of heating system that uses infrared radiation to directly heat objects and people in a room. SOLAR heat, with five letters, is a type of heating system that uses SOLAR energy to heat a building or space. Finally, STEAM heat, with five letters, is a type of heating system that uses STEAM to transfer heat from a boiler to radiators located throughout a building.