My $12 150 watt inverter, that doesn't even have a fan in it, runs TV, DVD, computers, PA sound system, small scooter and automotive batt chargers, and even my little 1 gallon pancake air compressor, but it will not run a little box fan correctly, same as my 1500 watt would not run the microwave correctly. And if you hang an AC volt meter on a MSW, you will really wonder whats going on. So, don't question it, it is what it is, it either works, or it doesn't. MSW has worked well for my needs, If I absolutely needed anything that didn't, I would spend some money on a PSW.