Have had ours save us more than once. Still scratching my head over two different campers told me the reason they did not use them. First said his wife would be to upset if it kept shutting off the electricity to there motorhome like mine was doing. Found out later he had to replace or repair AC, microwave, refrigerator and TV. Another time when I told the people next to us in the campground, they were sitting outside but there AC was on, that our unit was shutting down due to low voltage he told me that he did not need a unit like ours because he had a meter inside that told him what the voltage was. Still do not know how a meter inside when your outside does you any good.