Centralized cooling systems typically offer better efficiency than systems designed for individual rooms or units. Almost all air-conditioning systems work according to the same principles, so better efficiencies are generally obtained by using more advanced components.
Systems in 2015, while similar in principle to models used in the 1970s, can use up to 30 to 50 percent less energy. More efficient technology for compressing air via electricity leads to better system efficiency, while better refrigerants allow systems to remove heat faster. Improved insulation also allows systems to avoid leaking air where it is not wanted. Government regulations and industry standards allow consumers to determine the expected energy use of a system.