After having issues with both of our modified sine wave power inverters, we recently upgraded to a single pure sine wave inverter. You can find more detailed information on the difference between modified sine wave inverters and pure sine wave inverters here. The inverter that we upgraded to is one of the more affordable models, but after a couple weeks it seems to be doing fine under the stress of working virtually 24 hours a day. While pure sine wave inverters can be a little pricey, like most things, you get what you pay for.