The good people at Khosla Ventures seem to question the value proposition of straight solar panels (note the lack of c-Si in their portfolio).  But a potentially disruptive thin film firm like Stion warrants a Khosla investment.  And combining solar electricity harvest with solar heat seems to press Khosla Venture's buttons -- judging by the two investments the firm has made in hybrid solar electricity and heating firms Cogenra (covered a few weeks ago) and PVT Solar, which just completed a $13.7 million B round of funding led by Sigma Partners with Khosla Ventures and Energy & Environment Investment of Japan.

Vikas Desai has been appointed PVT Solar CEO.   Desai was previously VP and general manager of SunPower’s residential and light commercial business unit.  
PVT claims that their new solar energy system delivers twice the energy of a basic solar electric system and, as testament to that value, the company has won Meritage Homes, Joseph Carl Homes, and other homebuilders as customers, according to Fahri Diner at Sigma.   

The PVT system supplements conventional solar electric PV panels with a solar thermal technology that captures the heat from the PV panels -- generating electricity as well as transferring that heat to hot water for household use and thermal energy for home heating or home cooling.  

About 190 gigawatts of solar water heating is installed globally, according to Gilad Almogy, the CEO of Cogenra.  Compare that to the 20 gigawatts of solar photovoltaics installed on the ground (about 10 gigawatts of which was installed this year).  But you tend to hear a lot more about photovoltaics (PV) in the press and, admittedly, in this publication.  PV is a bit sexier -- there's a semiconductor aspect and a magical conversion of sun to electricity. Hot water is kind of dull by comparison. More importantly, as Michael Kanellos points out, tax credits for PV systems are more pervasive.  

Policy usually trumps technology, and in this case, policy seems to be on the side of solar hot water heating.  California Assembly Bill AB 1470 is The California Hot Water Heating and Efficiency Act authored by California Assemblyman Jared Huffman -- a $250 million incentive program for solar hot water heating.

Other early-stage companies looking to generate more than just electricity from the sun include Absolicon, Chromasun, Sundrum, Turkey's Solimpeks, Thrive Power, and Entech, which counts David Gelbaum as CEO.

The PVT architecture does require a creating a venting structure in the roof itself, usually in the attic of the house.  Judging by the firm's deals with homebuilders, this technique lends itself to new home builds.  And that's not exactly a booming market at this time.