You may get free hot water from a solar water heater but solar water heaters always have an electric water heater backup tank that WILL kick on if the water temperature doesn't reach it's 140 degree set point, which is happens more frequently than your rep may be aware of. We have received lots of feedback from homeowners who had a solar hot water systems added to their existing gas water heater where their electric bills actually went up!
By adding another water heater that is electric powered, your electricity use will unfortunately go up. It's an important distinction your solar hot water company rep may be blind to or may not disclose to you.
Solar hot water heaters use the sun to heat the water used for doing dishes, showers, laundry and in bathrooms and they are ideal for all electric homes with 3 or more occupants. Solar tax credits and rebates make solar affordable for everyone but it may not be suitable for everyone. Installing solar water heaters to homes may seem like a great idea but if your home uses natural gas for water heating, the old saying, "the grass is always greener on the other side" can apply to your water heater. Do yourself a favor and stick with your existing gas water heater and put the money towards insulating your walls or sealing your ductwork instead.
If you are looking to upgrade your existing gas water heater, look into a tankless water heater instead. For larger families, a 20 gallon storage tank is available for reserve water. Tankless water heaters are super efficient, only turning on when you turn on the hot water and instantly heating your water.