About 0.1 kWh per printing hour for a mainstream desktop machine. That is a 100 W draw, which puts a 3D printer somewhere between a laptop charger and a lamp — not in the same category as a kettle, an oven or a tumble dryer.
Energy, not money, is the useful unit here, because the price of a kilowatt-hour varies by a factor of four across the regions in this site's rate table while the consumption does not vary at all.
What a printer actually consumes
| Running time | Energy at 100 W |
|---|---|
| One hour | 0.1 kWh |
| A 12-hour overnight print | 1.2 kWh |
| A full 1 kg spool, start to finish | 2.184 kWh |
| Eight hours a day for a year | 292 kWh |
292 kWh a year is in the region of a domestic fridge, for a machine printing a third of every day. Most hobby printers do a small fraction of that.
The number that surprises people
A machine left switched on but not printing draws roughly 10 W — mainboard, display, fans, stepper drivers holding position. Left on continuously for a year, that idle draw alone is 87.6 kWh — close to a third of what the printing itself consumed in the row above.
If a printer sits idle far more than it prints, its standby is the larger half of its annual consumption. Switching it off at the wall between jobs saves more than any print setting will.
Wattage varies more than you would expect between machines
Bed size is the driver, because heating a large plate is most of the load. A 180 mm machine sits near 65 W while printing; a 256 mm one near 100 W; a 420 mm bed pushes 260 W. Enclosure heating and a chamber heater add more again.
Two cautions about the figures you will see quoted:
- A power-supply rating is not a consumption figure. A 350 W supply exists to survive the heat-up peak. Steady-state draw during a print is a fraction of it.
- Heat-up is a peak, not a rate. A bed pulling 850 W for the first few minutes contributes almost nothing to the total, because it is minutes against hours.
Thirty of the forty-two machines in the printer reference carry estimated rather than metered wattages, and each page says which. A plug-in energy meter costs very little and settles the question for your own machine permanently.
Multiply your own wattage by your own hours in the print cost calculator.