Quote: I use a 50W aq heater in a 3gal jug with horizontal nipples.
https://www.backyardchickens.com/a/aarts-heated-waterer-with-horizontal-nipples
Which uses less power would have to be tested with a killawatt.....lots depends on situation and setup.
@Leahs Mom did you check how warm that 250w kept the water?
I was more comfortable with the aq heater to keep water warm for HN's....and it only used about $3 a month of power.