What metric do flow meters specifically measure?

Flow meters are designed specifically to measure the flow rate of a fluid as it moves through a system. This metric is crucial in various applications, including HVAC systems, where maintaining the right fluid flow is essential for optimal performance and efficiency. Flow meters can provide real-time data on how much fluid is moving within the system, allowing technicians and engineers to monitor and control processes effectively.

Flow rate is typically measured in units such as gallons per minute (GPM) or liters per second (L/s), depending on the application and the type of fluid being measured. By accurately measuring fluid flow rate, flow meters help ensure that systems operate within their designed parameters, which can improve energy efficiency and reduce wear and tear on components.

The other options, while relevant to various aspects of HVAC and fluid mechanics, do not pertain directly to what flow meters measure. Temperature refers to the heat level of a substance, humidity indicates the amount of moisture in the air, and fluid density measures the mass per unit volume of a fluid. These are important metrics in their own right but are not functions of flow meters.