Convective: Heat transfer caused by movement of air. An energized molecule is moved through forced air. Air infiltration and leakage of conditioned air is the most costly to homeowners. It must be controlled by creating an air barrier that stops air movement and is not affected by the stack effect or pressure differentials in the building. Creating a building envelope that is in control mitigates convective heat transfer. (picture foam, BIBs, visqueen)

Conductive: The direct flow of heat through materials from physical contact. This is known in the industry as thermal bridging where an energized molecule energizes an adjacent molecule. There any many techniques to mitigate this but the concept is to create a break in the “bridge” with a low conductivity material or no material at all. (picture FLIR, house wrap or ICF)

Radiative: Energy transfer through space via electromagnetic waves. Radiation travels from a heat source linearly until is reaches a material that absorbs that radiation at an empirical emissivity rate. Material, like aluminum has low emissivity and reflect up to 97% of the radiation directed at it making it a very effective radiant barrier. (pic foil and house, house wrap)

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