There is an article on exoplanet hosting stars that shows how different our solar system is to those that have been observed in the referenced paper. (landscheidt.info)
For general information on savings, the Solar Rating and Certification Corporation (SRCC), publishes Solar Energy Factors, which can be used to compare different solar systems (with electric backup only) to other water heaters under national average weather conditions. (peakoil.net)
Two interesting possibilities are that Sedna might have been tugged into its current orbit by a passing star, or may have been captured from a different solar system. (kavliprize.org)