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100-device scenario

Calculate after-hours energy from measured PC and monitor power.

There is no honest universal answer to “what do 100 PCs cost overnight?” Enter the measured current state, target state, managed share, time and your own billing rate.

Measurement first

Do not publish a generic “100 PCs use this much” claim.

Hardware, monitor count, sleep policy, remote access and updates create different results. Use representative measurements and your current bill.

Interactive calculator

Office PC after-hours energy calculator

Results update when an input changes.

Enter your measured idle or sleep value.
Use a measured value after a safe shutdown policy.
Adapt working days, nights and weekends to your organisation.
Replace the example with your effective billed rate.
Leave monitor count at zero to exclude displays.
Estimated monthly cost difference
261.12 cost unitsdifference between the measured current and target scenarios
Monthly energy difference1,305.6 kWh
Current after-hours energy1,360 kWh
Target after-hours energy54.4 kWh
Annual theoretical cost difference3,133.44 cost units
Managed devices100

This is the mathematical difference between your measurement, time and rate inputs. It is not a guaranteed saving or bill forecast.

How the calculation works

Monthly kWh difference
managed PCs × ((current W − target W) + monitor difference) × after-hours ÷ 1,000

Multiply the kWh difference by the rate from your bill for a cost scenario. Keep currency, taxes and tariff period visible in any report.

Why realistic scenarios differ

Higher baselineIdle PCs left running

Active services, peripherals and displays can keep after-hours watts far above a true off state.

Lower baselineManaged sleep or shutdown

A mature endpoint policy may already leave little avoidable energy; measurement prevents double-counting.

Measure the exact endpoint

Record at least several normal days. Separate active, idle, sleep, soft-off and fully de-energised states. Include docking stations and monitors only when they share the measured boundary. A PSU label is not a measurement.

Measurement evidence

Use live readings and recent history together.

Smart Kablo mobile electrical measurements for a connected device
Current stateRecord the state and available electrical measurements.
Smart Kablo mobile 24-hour energy history
Time patternCheck whether the measured state persists after working hours.

A safe 100-PC rollout

  1. Pilot representative PC, monitor and docking-station models.
  2. Use endpoint management for a graceful operating-system shutdown.
  3. Exclude devices with overnight updates, remote access or critical services.
  4. Verify measured power reaches the intended target state.
  5. Test startup behaviour and user impact before expanding the policy.
  6. Compare a second measured period against the baseline.
Never use abrupt relay opening as a routine shutdown method. Smart Kablo controls compatible input power; it does not close applications or protect pending writes.

Compatibility limits

Every connected device must remain within the 5 A continuous-current limit. Verify voltage, frequency, protective earth, source and equipment connectors, measured current and startup behaviour. Compatibility cannot be inferred from “desktop PC” or a country name alone.

Why does the calculator default to 100 PCs?

It mirrors the example question. Replace all values with your measured estate.

Does the target value mean zero watts?

Not necessarily. Wake features, adapters and controls may retain a small load. Measure the actual target state.

Is the cost result guaranteed?

No. It is a scenario based entirely on the values entered.

Related guides

Planning

Office PC energy savings

Build a measurement-led policy.

Remote access

Turn on a PC remotely

Compare WOL and AC Recovery.

Scale

Multi-site power monitoring

Organise distributed-device visibility.

Start with a measured pilot, not a generic estimate.

Plan a compatibility review