I gave myself seven years because they're typically only warrantied for five. It's a new technology that basically puts an air conditioner on top of the water heater, and instead of blowing the hot air outside of your house, it shoves it into your water.

Even though it's built like a tank, there's always the chance of early failure because the system is far more complex than "electricity through resistive coil makes heat" like normal electric water heaters.