These inverters are primarily used for grid-tie purposes but also have the added feature that they provide backup power to your home / office when the electric utility fails.
These inverters are principally meant to be used with solar for a home or business totally disconnected from the electric utility company. They can also be used for providing emergency backup power to homes that currently use the power from an electric company. Inverters with the built-in AC charger option are particularly well suited to providing seamless backup power.
Inverters which are connected to your electric utility company and do not use a battery bank. These "grid-tie" systems tend to be lower in cost due to the fact that they don't use batteries. However, if the utility company's power goes down then your system will also shut down. If blackouts are frequent in your location or you want to have backup power, consider purchasing an inverter that is Hybrid.