I like to use this analogy to give one an alternative way to consider the plasma output.
The plasma output is 40 watts.
Your home WiFi router is by law limited to 1 watt, and typically is less.
Consider how far the WiFi router reaches your phone, and then you can put into perspective how far the plasma output reaches without trouble.
Granted the further away you are, the less power it carries. While we suggest use of the near field (6 inches out from the tube/bulb), if you make use of the far field, try to remain within 5 feet for better efficacy.
I have seen changes in a target that was 60 feet away behind 4 walls. However, efficacy was much greater when this same target was 10 feet away.
For more details, please check the link: