Of all the different models that we looked into, the AeraMax 300, Blueair Blue Pure 211+, and Coway AP-1512HH were by far the most energy-efficient. Each of these models can be operated at different speeds, which helps to control the amount of energy that they consume. They also feature an eco-mode, which allows you to save even more electricity while still effectively removing smoke and other particles from the air in your home.