Plastics, or polymers, are low-cost materials that show good corrosion resistance, fair strength and low weight. This would make polymers excellent replacement materials for the heavy, expensive and corrosion sensitive metals used in most heat exchangers. This could result in reduced weight of vehicles improving the fuel economy, better functioning desalination plants for providing cheaper potable water and plenty of other possibilities. The only problem here is that polymers are thermal insulators. This problem can be solved by adding heat conducting materials as a filler in the polymer matrix, thus making a composite. This poster covers the basics of thermal conductivity in polymer composites.