SunEdison has promised that when it gets deeper into residential solar financing, it's going to do things a bit differently.

How about financing solar electricity and solar hot water for residential customers?

SunEdison will do that through its acquisition of Khosla Ventures-funded EchoFirst (the former PVT Solar). The price was not disclosed. The startup's technology provides air temperature control to the customer along with the photovoltaic panels and solar hot water.

SunEdison did not comment on the acquisition and its communications people seemed surprised by the news. Multiple sources close to the company have confirmed that the deal closed last week. EchoFirst has not responded. The company's technology promises solar power, energy storage, and quicker payback.

In 2010, EchoFirst raised a $13.7 million round B and named Vikas Desai CEO of the hybrid electric solar and solar hot water firm. Desai was previously VP and general manager of SunPower’s residential and light commercial business unit. Investors included Sigma Partners, Khosla Ventures and Energy & Environment Investment of Japan. Combining solar electricity harvest with solar heat seems to press Khosla Venture's buttons -- the company has also invested in hybrid solar electricity and heating firm Cogenra

EchoFirst claims that this is the first no-money-down combined solar electric and solar thermal lease for the residential market. The company's website reads, "And with a dedicated fund of $50 million, just as our first step, we've got the financial strength to service our customers across the country."

It's WGL Holdings (WGL) which is providing the $50 million in project capital for EchoFirst. WGL has similar "arrangements" with American Solar Direct and Skyline Innovations.

Earlier in its history. EchoFirst won Meritage Homes, Joseph Carl Homes, and other homebuilders as customers, according to Fahri Diner, an investor at Sigma. The firm is working with homebuilders in California, Nevada, Florida, Texas, North Carolina, Utah and Arizona. The thermal architecture does require a venting structure in the roof, usually in the attic of the house. Judging by the firm's deals, this technique might better lend itself to new home builds.

Other companies looking to generate more than just electricity from the sun include Absolicon, Chromasun, and Turkey's Solimpeks