Estimate switch power draw, annual energy use, cooling load and electricity cost across a fleet.
The power a switch pulls from the wall is its internal load divided by the power supply's efficiency, so a 90%-efficient PSU draws about 11% more than the load suggests. Multiplying by PUE accounts for cooling and distribution, and every watt of IT load becomes 3.412 BTU/hour of heat to remove. Network power is a recurring operational cost and a hard constraint on rack density, so the cooling figure often decides how many switches a cabinet can hold long before the rack units run out.
Switch Power Consumption
draw = (idle + PoE load) ÷ PSU efficiency; facility draw = IT draw × PUE; annual kWh = facility kW × 8760.
draw = (idle + PoE load) ÷ PSU efficiency; facility draw = IT draw × PUE; annual kWh = facility kW × 8760. The power a switch pulls from the wall is its internal load divided by the power supply's efficiency, so a 90%-efficient PSU draws about 11% more than the load suggests. Multiplying by PUE accounts for cooling and distribution, and every watt of IT load becomes 3.412 BTU/hour of heat to remove.
Network power is a recurring operational cost and a hard constraint on rack density, so the cooling figure often decides how many switches a cabinet can hold long before the rack units run out.
This calculator takes 6 inputs: Switches in the fleet, Chassis idle draw per switch, PoE load per switch, Power supply efficiency, Electricity cost, Data centre PUE. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.