Grid tied homes are connected to the electric utility lines. This allows the home to utilize and/or store solar electricity when the sun is shining and to use utility power when the sun is not out. In the event of a utility power failure, this type of system can automatically switch over to battery power. While the utility power is out, this house functions as an off-grid home. When the power comes back on, the system automatically switches back to using a combination of solar and grid-power. The homeowner may never even know there has been a power failure.