Recurve, one of the companies that helped bring attention to home energy audits and retrofits, is undergoing some remodeling itself.

The company is shifting its construction group, which performs the audits and carries out work inside homes, to Advanced Home Energy, a retrofitter in the East Bay. Recurve itself will become a software developer with around 20 employees, said co-founder Matt Golden.

The split is not completely a surprise, but it does represent a change of plans. Last year, Recurve got a new CEO, Andy Leventhal, and announced it would split into two divisions: a software group and a construction group. The construction group under the original plan, however, was going to remain a subsidiary.

The challenge has been keeping to relatively different types of businesses under one roof. Like many other green building companies, Recurve has been walloped by the downturn in construction.

Politics haven't helped either. In 2010, momentum was building for retrofitting. PACE, a financial model in which consumers could retrofit their homes and pay for the work through supplemental property tax payments, was touted by Vice President Joe Biden and others as a way to create green jobs and reduce energy consumption. Golden, among others, had even envisioned programs where home retrofits could be funded through forward capacity deals: rather than build new plants, a utility would retrofit homes to reduce demand. Data -- lots of it -- would be needed, but conceptually it is possible.

Fannie Mae and Freddie Mac, however, opposed the PACE program, claiming that PACE could hurt lenders. Although several states had already passed PACE programs, the concept was effectively halted. Today, it is still on hold. Some solar companies, weirdly, came out against PACE, too.

Recurve's software examines data from different retrofits to try to determine the optimal retrofit package for the next one and, ideally, to reduce the time and cost of each project. (Retroficiency, out of MIT, has similar software for commercial buildings.) Recurve, formally known as Sustainable Spaces, started working on the software strategy in 2009 and even started hiring Google employees. (See the first story on Recurve's software strategy here, as well as Post-It notes diagramming a decision tree in this photo of Golden.)

The company is currently conducting trials with large contractors. It is also trying to get the software certified so that it can be used in various state retrofitting programs. In California, for instance, homeowners can get $3,500 in rebates for retrofitting and the City of San Francisco will throw in another $2,000 for a limited time. (Disclosure: Recurve did our house, a 1931 number that had almost no insulation. We paid full price. It is noticeably warmer and more comfortable now thanks to the open-cell foam insulation, among other tweaks.)

Golden, however, admitted that retrofitters face budget battles with these programs, too. Although the Department of Energy is providing matching funds in many instances and is gung-ho on efficiency, some states are contemplating pulling back on energy programs.