The cost of running a building's air conditioning (AC) system when everyone leaves work at night can vary depending on several factors, including the size of the building, the efficiency of the AC system, local energy rates, and climate conditions. Here are some considerations to help estimate the cost:
AC system efficiency: The energy efficiency rating of the AC system plays a significant role in energy consumption. Higher efficiency systems generally consume less energy and cost less to operate. Look for the Seasonal Energy Efficiency Ratio (SEER) rating of the AC unit to determine its efficiency.
Building size and cooling load: Larger buildings require more cooling capacity, resulting in higher energy consumption. The cooling load depends on factors such as the building's size, insulation, windows, and heat-generating equipment. The higher the cooling load, the more energy the AC system will consume.
Setback or setback temperature: If you implement a setback strategy where the AC system is set to a higher temperature or turned off when the building is unoccupied at night, it will help save energy and reduce costs. The setback temperature should be set high enough to limit cooling but still maintain a comfortable environment.
Energy rates: The cost of electricity can vary based on your location and energy provider. Check your energy bill or contact your utility company to determine the energy rates applicable to your building.
To estimate the cost, you can use the following formula:
Cost = Power (kW) x Time (hours) x Energy Rate ($/kWh)
Determine the power consumption of the AC system in kilowatts (kW). This information can typically be found on the AC unit's nameplate or in the system specifications.
Determine the duration the AC system operates when everyone leaves work at night.
Contact your utility company or refer to your energy bill to obtain the energy rate in dollars per kilowatt-hour ($/kWh).
Multiply the power consumption by the operating time and the energy rate to calculate the estimated cost of running the AC system during that period.
Keep in mind that this is a rough estimation, and actual costs can vary. For a more accurate estimate, consider installing energy monitoring systems or consult with your utility company for energy usage data specific to your building.