In the United States up to 40% of all energy used is consumed by commercial and residential structures. Nearly 40% of that energy is spent on Heating or Cooling the building. According to officials at Oak Ridge National labs, the US Department of Energy and many other third party testing and accreditation Labs, the use of properly formulated and placed PCMs within the structure can reduce the heating and cooling load by between 40% to 60%. The use of PCMs in buildings within the United States then has the potential of saving Quadrillions of BTUs of energy every year, reduce our dependency on foreign energy sources, and significantly reduce our carbon footprint.
For use in construction, PCMs would ideally have melting points just above room temperatures such that they are still solid at room temperature. Any increase in room temperature causes them to melt thus absorbing heat from its surroundings. A reduction in temperature to below the phase change temperature would result in heat being released to the surrounding air again. Consequently the use of PCMs aids in removing fluctuations in room temperature, thus reducing heating and cooling loads.