3D printing is an emerging technique in product manufac- turing. Its applications have been expanding vastly in home- based production. Compared to traditional manufacturing techniques, such as Computerized Numeric Control (CNC) machine tools, it is believed that 3D printing is more cost- effective in fabricating personalized products. The product cost estimation in 3D printing mainly takes material expen- diture into account, and extensive studies have been per- formed for reducing filament expense or development of re- cyclable filaments. However, electricity expenditure is an- other inevitable cost in the 3D printing process yet an omit- ted factor in the cost estimation. To this end, this paper intro- duces the first in-depth study to understand the energy con- sumption in 3D printing. Specifically, our study comprises of two parts. The first part quantifies both material and electric- ity use in the 3D printing, and find that the electricity takes upto 32% of the total cost. The second part characterizes the energy consumption and identifies the sensitivity of various parameters. We also share insights and potential solutions to optimize the power consumption of 3D printers.