Multimedia learning environments such as computer simulations are widely accepted as tools for supporting science learning. Although the design of multimedia learning environments can be domain specific, few studies have focused on the use of computer simulations for learning residential electrical wiring. This study aimed to determine whether students using computer simulations learned better than traditional classroom learners in the domain of residential wiring. A quasi-experiment was implemented with 169 high school students. The simulation group participated in a series of computer simulations, whereas the control group received lectures and demonstrations from an instructor. Students' cognitive load as elevated by multimedia leaning tasks was compared with that of students learning using traditional methods. The simulation group learned significantly better and reported higher cognitive load than did the control group. Moreover, the simulation group managed cognitive resources more efficiently on transfer of learning than did the control group. Having more opportunities to interact with a simulation-based learning environment could result in higher cognitive load. The higher cognitive load seemed to result in better performance on the achievement test and, therefore, the learners' mental effort was possibly invested mainly in meaning making in the virtual learning environments. Discussion of the results, instruments and research design, as well as suggestions for future studies are provided.