An economiser is a device utilized for energy conservation, which is typically installed in heating and cooling systems. It functions by decreasing the volume of energy required to sustain the system's operation. Another term for an economiser is an energy recovery system, which is designed to harvest the energy produced by a heating system's exhaust gases. Energy recovery ventilator (ERV) and heat recovery ventilator (HRV) are also synonyms for this phrase. In addition, there are various other synonyms for an economiser, including a thermal wheel, heat exchanger, and an air-to-air heat exchanger. The usage of these synonyms is determined by the specific characteristics of the device being utilized to maintain the energy system in place.