Which metric is used to measure energy consumption over time?

The Kilowatt-hour (kWh) is the metric commonly used to measure energy consumption over time. This unit quantifies the amount of energy used by a device or system over a period, specifically combining power (in kilowatts) with time (in hours). This makes it particularly useful for understanding how much electricity is consumed by homes, businesses, and appliances, as it reflects both the intensity of power usage and the duration of that usage.

In contrast, other options are not suitable for measuring energy consumption over time. Volt-amperes (VA) are units for measuring apparent power in an electrical system, which does not directly account for energy usage over time. Megawatts (MW) represent a rate of power, indicating the amount of energy produced or consumed instantaneously, but like VA, it doesn’t provide a measure of total energy consumed over time. Fahrenheit (°F) is a scale for measuring temperature, which is unrelated to energy metrics. Therefore, the Kilowatt-hour is the most appropriate choice for the context of measuring energy consumption across time.