Vivint Solar (VSLR) is now at the NYSE after pricing at the low range of its initial public offering at $16 a share. Vivint Solar designs, installs and maintains solar energy systems for residences and is backed by Blackstone Group (BX). The company's CEO Greg Butterfield spoke to TheStreet on its IPO and competing with Elon Musk's SolarCity (SCTY), which is the largest installer of residential solar panels in the U.S. Solar is growing at a shocking rate but still only provides less than half a percent of America's electricity. Interestingly, most of Vivint Solar's growth has come for door-to-door sales.