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Acquaintia

PC energy cost calculator

What do your PCs cost when nobody needs them?

Enter your own figures. The calculator works out the electricity, cost and carbon of the hours your PCs are on but not needed, over a year.

Your figures

Example values are filled in. Replace them with yours.

PCs

The PCs that stay on outside working hours.

watts

Including the monitor. A plug-in energy meter on a few typical machines gives a good figure.

watts

Leave at 0 if you don’t know it. The result then counts a sleeping PC as using nothing.

pence per kWh

From your electricity bill.

hours

168 means on all week.

hours

Your working hours, plus any time set aside for maintenance.

kg CO2e per kWh

The example is the UK government’s 2026 factor for grid electricity.

The hours nobody needs, over a year

Cost
—
Electricity
—
Carbon
—
Per PC
—
Unneeded hours per PC
—

Compared with the same hours asleep.

How it's worked out

Four multiplications, nothing hidden.

  1. Unneeded hours per PC = (hours a week on − hours a week needed) × 52.14 weeks
  2. Electricity = PCs × unneeded hours × (draw when on − draw asleep) ÷ 1,000, in kWh
  3. Cost = electricity × price per kWh
  4. Carbon = electricity × carbon factor, in tonnes of CO2e

From one average to every PC

One average draw and one set of hours can only take you so far. Acquaintia works the same sums for every PC: its own wattage profile, the hours it actually spent active, idle, asleep and off, and the tariff and carbon factor for its location. Then it puts idle PCs to sleep, and reports the change against a baseline.

How Acquaintia estimates energy

Carbon factor: Department for Energy Security and Net Zero, Greenhouse gas reporting: conversion factors 2026, published 11 June 2026. UK electricity generated, Scope 2.

Questions

How much power does an idle PC use?

It depends on the processor, the power supply and, above all, the monitor. The rating plate gives a maximum rather than a typical figure. Measuring a few typical machines with a plug-in energy meter gives a better one. Acquaintia estimates it for every PC from wattage profiles for each make and model.

Which carbon factor does the calculator use?

The example is 0.13096 kg CO2e per kWh, the 2026 greenhouse gas conversion factor for UK grid electricity from the Department for Energy Security and Net Zero. Replace it with the factor your organisation reports with.

Does this tell me what Acquaintia would save?

It tells you what the hours nobody needs cost, on your figures. How much of that a sleep policy recovers depends on how your PCs are used, which is what Acquaintia’s baselines and savings reports measure.

Turn this number into a report.

Book a demo and we'll show you the same figures for every PC, from your own hardware and hours.

Book a demo

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