Vivint, one of the country’s biggest home alarm system companies, which has been branching out into offering its customers solar power financing and services recently, is being acquired for more than $2 billion by The Blackstone Group, according to the companies. Consider it another big investment in the growing third-party residential rooftop solar space.

Under the terms of the deal announced Wednesday, Vivint investors Goldman Sachs, Jupiter Partners and Peterson Partners will sell their shares in the company to give Blackstone more than 50 percent control of the private equity-backed company. That includes Vivint Solar, the Provo, Utah-based company's third-party solar business, as well as 2Gig Technologies, a home device maker which is partly owned by Vivint executives.

Vivint switched its name from APX in 2011 after a $565 million senior debt financing from previous equity investor Goldman Sachs, and has about 675,000 customers of its home security and automation services across the country. As for its solar efforts, it started them in New Jersey and Massachusetts last year and expanded to Hawaii in May. In July, it branched out into California, where third-party solar pioneers such such as SolarCity, Sungevity and Sunrun have brought more than half of the residential rooftop solar in the state under the third-party ownership model.

Vivint has lined up some hefty financial backers, including US Bancorp, which pledged a $75 million fund for the company’s solar business in March. In February, Kleiner Perkins and Google-backed startup Clean Power Finance announced it was working with Vivint as one of a number of partners it was using to pursue its own third-party solar financing plans.

The company also has some ambitious growth plans, according to an interview with Vivint CEO Todd Pedersen, who told Fortune that the company plans to be "the largest developer of residential solar in North America by many times over at the end of this year," He also mentioned the planned IPO for third-party-financed solar pioneer SolarCity, noting that, "If it's successful, and we hope they are, it's possible that our solar division could do an IPO with our parent company remaining private."

In our July story on Vivint's launch in California, President Tanguy Serra discussed how the company is moving into solar from its strength in home automation and customer service, starting with keeping customers informed on how the system is providing green power in an up-to-date fashion. Here's our previous coverage of the company:

“Right now, we use the homeowners’ broadband to monitor the panels and the power produced,” Serra said. “Every month, we send the homeowners a bill for the amount of solar power they use … and we monitor in real-time to make sure the array is working.”

That setup runs on the same technology that Vivint now uses for its home security and automation systems, he said. Vivint connects to its home controller panel via GSM cellular, and thence to smart thermostats, lighting control systems, door locks, security cameras and other in-home devices via Z-Wave, the proprietary wireless technology that’s also being used by such would-be home automation players as Verizon.

Those thermostats, lights and other energy-using home systems can already be pre-programmed to turn themselves down when people leave their houses, or can remotely controlled via smartphone while they’re away, he noted. Now Vivint is working on a “generation 2.0” platform that can record up-to-date solar power output at the home, he said -- and that, in turn, could lead to linkages with home energy management

“Because you’ve got this remote control panel with a big touchscreen display, we’ll be showing the homeowners usage, as well as the solar production, on that panel,” he said. “If you show a power curve of when their solar power is produced, […] you can adjust people’s consumption behavior,” such as encouraging them to turn on energy-hog devices like dishwashers and clothes dryers when the solar system is cranking out the most kilowatts per hour, he said.  

All of them connect via Vivint’s home gateway to a cloud-based system that’s accessible via website or smartphone. “If you log onto your own personal account, you can select the rules you want to apply, whether you want to be aggressive, or less aggressive, on saving your energy,” Serra said -- a set of features common to many of the companies contending for a slice of the as-yet-unformed home energy management market.

The company is also looking at more sophisticated applications, like pre-cooling homes using solar power when it’s at its peak production -- say, 3 p.m. to 5 p.m. -- and then letting air conditioners idle through the hours when people come home from work, to avoid stressing the grid, he said.

Vivint is working with 2Gig, to build its home automation devices, which it has been selling as part of its service since 2009, and it also works with Radio Thermostat Co. of America for smart thermostats, he said. On the solar side, Vivint uses Enphase Energy microinverters and Zep Solar mounting systems.

Of course, Vivint doesn’t have a monopoly on the idea of combining residential solar with home energy management. Big third-party residential solar financing companies like SolarCity have been monitoring and managing their “fleet” of solar systems for some time now, and could bridge into home energy management as an add-on to their solar installations. Indeed, SolarCity has also been testing out lithium-ion batteries from Tesla Motors to back up its solar rooftops.

Vivint has about 50,000 home automation system customers in California, Serra said, compared to about 100,000 in Texas and more than 100,000 in the Northeast, where it has concentrated its solar business so far.

Serra told us in February that the company was on target for 3,000 to 5,000 solar installations per year in its first six months in the business, and hoped to grow the business to match the 150,000 home system installations or so it does annually.

Of course, Vivint isn’t limited to pitching its existing customers for solar systems either. In fact, Serra said, solar sales could open the door to home security and automation sales.

Think of it this way: for the amount of money a homeowner can save on their monthly power bills with a third-party-financed solar system, they can cover, or at least partly cover, the $50 to $69 per month cost of Vivint’s home automation system.

As far as combining the still-expensive costs of home automation with a target market that has shown its interest in going green by asking to learn more about solar, it isn’t the worst sales pitch we’ve heard so far. 

Tags: california, clean power finance, home energy, pv, residential solar, smart thermostat, solar, solar panels, solarcity, sungevity, sunpower, sunrun, suntech, third-party financed, vivint