The Oakland, Calif., company announced the new funding, along with a separate, venture capital round of $40 million on Wednesday. Sungevity began raising that $40 million in early 2012 and closed the round before the end of year. The new capital will not only enable the company to market its services to residential customers, it also will likely be spent on rolling out services beyond putting solar panels on the rooftops. Birch hinted that the company is working on a “road map of new services” that are related to energy, but declined to specify what they are.

Its competitor, SolarCity, has expanded its offerings beyond solar panel installations in recent years by offering lithium-ion battery systems from Tesla Motors for storing electricity produced from solar panels (the batteries discharge the energy whenever it’s needed, such as at night when solar panels aren’t able to producing electricity). It also inspects homes and carries out retrofits, such as putting in a more energy efficient air conditioning system and insulating the air duct.

Unlike SolarCity, Sungevity doesn’t keep in-house crews for installing solar panels. Instead, it hires local contractors, such as electricians and roofers, to do the work. The success of both companies depends heavily on their ability to raise money to finance installations. Aside from selling solar energy equipment directly to homeowners, they also offer 20-year leases in which homeowners pay a monthly fee for the solar electricity generated from their rooftop systems, which are in turn owned by banks or other investors who put up the money to install them.

The two companies, along with rivals such as SunRun, Clean Power Finance, OneRoof Energy and Vivint Solar, have driven the growth of solar leases, which many consumers see as a more affordable way to get solar electricity.

From the start, Sungevity devoted considerable resources to developing software to more efficiently customize solar equipment installation to fit the different sizes, angles and orientation of its customers’ rooftops. The company hired the former chief marketing officer of LinkedIn, Patrick Crane, in 2011 to figure out how to use social media and personal referrals to attract more customers. Since his arrival, about a third of the new customers came from referrals, Birch said. Other marketing strategies have made use of its connection with Lowe’s, which invested in Sungevity and now offers solar installations through the startup. Sungevity also has pledged to donate to Sierra Club for every Sierra Club member who chooses Sungevity.

“We see a world where the vast majority of the leads are coming from existing, very happy customers,” Birch said.

The company has signed up over 5,000 customers since its inception in 2007, Birch said. Sungevity’s goal is to double the number of solar energy installations and the megawatts involved every year, he said.

The $85 million project financing fund came from Energy Capital Partners and a bank that has declined to disclose its name. The fund is a combination of tax equity and mezzanine financing. The tax equity portion is due to provide the investors with returns within a shorter period of time, around five years, and it allows the investors to take advantage of the 30% federal investment tax credit for solar energy installations. The mezzanine financing provides the tax benefit, but it also counts on the payments from the 20-year leases signed by homeowners in determining the return on the investments.

Tax equity funds have been a popular way for solar companies to finance installations, but their existence is tied to the federal tax credit, which is due to expire by the end of 2016. As a result, solar service companies have been looking for other ways to raise capital. SolarCity went public last December and is reportedly working on issuing securities that will be backed by its solar leases, much like the mortgage-backed securities.

Birch said the mezzanine financing structure shares similarities with solar asset-backed securities. Sungevity is interested in solar-backed securities as well, though he declined to say when the company will likely use this method to raise money.