The power use of a 3D printer is complex. The CR-10 is a loud machine, which can make it seem as though it is using a lot of energy. However, its main power draw is its heated printing bed.

Below I've illustrated some of the phases of a print job, and the power use I measured during those phases.

When the printer is powered on, the controller board and fans in the control box use 11 watts of power. This is pretty loud.

To heat the print nozzle to a temperature that can melt PLA plastic, the printer uses more energy. Just being on with the nozzle at 185, it uses 55 watts.

Once the nozzle is heated, a little less energy is needed to keep the hot nozzle hot: 34 watts.

The highest power use kicks in during those times when the printer is heating the platform, or bed of the printer. When the bed heating is engaged, with the other power use, the printer uses 275 watts.

But, the bed has a thermostat, so it only uses energy when the temperature dips. During a regular print, the bed stays warm, which uses power in an on-off-on-off cycle, sometimes for hours. About half of the time the printer is only using 54 watts, but at other times the printer is using 275 watts, as the bed is heating. On average, I estimate the printer uses 180 watts when it prints with a warm bed.

If the bed isn't being heated, the printer is just heating the nozzle and running the control computer, the fans and the two or three motors. This uses 62 watts.

In California, baseline residential electricity costs 12¢ a Kilowatt, so running a printer at 180 watts costs about 2¢ an hour.

2¢ an hour is cheap.

If you ran your printer continuously, 24 hours a day, 7 days a week, for a month, it would cost about $15, the same price as HBO Now.