Sunrun, fresh off of its IPO announcement, has something else to celebrate. In the first quarter of the year, it installed more residentialsolarthan any other firm not named SolarCity or Vivint Solar. That’s according to the latest edition of GTM Research’s U.S. PV Leaderboard, released today.

FIGURE: U.S. Residential Solar Installer Market Shares, Q1 2015

Source: GTM Research U.S. PV Leaderboard

While SolarCity and Vivint continued to dominate the U.S. residential solar market with a combined market share of 45 percent in Q1 2015, it’s a close race for the No. 3 spot. Sunrun installed 3 percent of U.S. residential solar in the first quarter of the year, and Sungevity and NRG Home Solar were close behind, both installing 2 percent.

Any of these three firms have the potential to be the third-ranked installer by the end of 2015. Nicole Litvak, senior solar analyst at GTM Research, provides the case for each.

Sunrun

Vivint Solar experienced a huge growth spurt leading up to its IPO in October 2014. If Sunrun can do the same and hold onto that momentum, it has a good shot at maintaining its current No. 3 position. Sunrun has been successful so far in scaling up its direct sales business since acquiring the residential division of REC Solar in early 2014. Recent developments include the introduction of a loan, the acquisition of lead aggregator Clean Energy Experts, and partnerships with Comcast and Ambit Energy (among others). Direct sales now account for about 25 percent of the company’s total deployments, with the remaining 75 percent coming from Sunrun’s installer partners.

Sungevity

Sungevity is defying the theory that vertical integration is the only way to scale in residential solar. Unlike the other four top installers, Sungevity is moving away from vertical integration. The company used to finance all of its own systems, but as of last year, Sunrun finances most of Sungevity’s deals. Sungevity also uses subcontractors for all installations, focusing all of its efforts on the sales portion of the value chain. It does this entirely via phone and online sales and has built a strong platform for lead generation based on advertising, direct mail, and channel partnerships.

NRG Home Solar

After acquiring Roof Diagnostics Solar in early 2014, NRG Home Solar continued to beef up its residential business with the additional acquisitions of Pure Energies and the Northeast sales and operations teams of Verengo Solar. While NRG isn’t active in as many states as the top four, it has a strong brand name in the Northeast. It is among the top three (along with SolarCity and Vivint) in Massachusetts, New York, and New Jersey. In order to break into the national top three and reach its lofty goals for 2015, NRG Home Solar will need to gain momentum in California, where it expanded last year but has yet to reach any significant scale.

The U.S. installed 437 megawatts of residential solar in the first quarter of the year. GTM Research forecasts the U.S. to install 2 gigawatts of residential solar in 2015.

***

GTM Research's U.S. PV Leaderboard tracks quarterly market share for installers, inverter suppliers, and module manufacturers in the residential and commercial market segments. Learn more about the Leaderboard here.