It does take a few minutes to warm so the middle of the night may be a pain. When I stopped bf the night feedings were long gone so I'm sure the lo will get a little anxious waiting. In the day the only feeding that he gets a little worked up is when he wakes first thing in the morning. Anyway, all I do is boil water in the kettle, then pour the hot water into a tall container and stand the bottle in it and let it warm. Takes a few minutes and the only thing is if you shake the milk in the bottle that will cause bubbles and give gas. The instructions recommend mixing in a different container and then pouring into the bottle. Not sure how to work that out though. I have never used an electric warmer so I don't know about the lowest setting. Maybe you can judge that, if it doesn't get any hotter than just-boiled water it might be ok. Good luck!