Do the solar electric and thermal systems need backup?
Backup is wise for any system, particularly in parts of the country where sunlight is not a guarantee on a steady basis. Most homeowners tie their system to the electricity grid, allowing extra power to be sold to the electric company at high rates and power to be drawn back off the grid at low rates during hours of darkness. This is known as a net metered, grid-tied system; the utility company is your backup. Solar water heating systems use a hot water tank for storing hot water. A gas line can be run to it or it can be set up with an electric heat element with an on / off switch for additional backup.
