The meter may be considered the most important single piece of apparatus in any facility engaged in the distribution of thermal energy. Central energy systems must obtain their revenue on the basis of meter readings. These meter readings must be accurate and meet local utility regulations. In non-commercial situations meters are essential to effective energy saving efforts. The selection of meters is critical to the financial stability of the enterprise, whether it be profit or non-profit. Progress in hot and chilled water measurements in the past decade has not been outstanding due principally to the lack of good markets