UPDATED 12/15/2010: With additional details from Domus Development.

When money is no object, the pursuit of green (and green) in homebuilding has been known to include some pretty extravagant renewable-energy systems, on top of whatever energy efficiency details are built into the envelope. Recent examples: the 4,539-sq.-ft. first-place winner of the 2010 Connecticut Zero Energy Challenge, which includes a geothermal system and extensive solar power system, and a 5,000-sq.-ft. LEED Platinum home in California with a $2.3 million listing price.

But as is justifiably the case, projects that achieve energy efficiency at a relatively low price tend to generate more curiousity among builders. The second-place winner of the CT Zero Energy Challenge came in at 2,690 sq. ft. and about $320,000 in construction costs, and a Green Mountain Habitat for Humanity project in Charlotte, Vermont, is aiming for Passive House performance. And last week, a news report surfaced about groundbreaking on another project aiming to merge low construction costs with energy efficiency, a housing-and-commercial development just north of downtown Sacramento, California, that will include 81 units and about 5,000 sq. ft. of commercial space.

A tie-in to light rail

The housing plan has two parts: a four-story mixed-use building with 63 apartments in various configurations (9 studios, 24 one-bedrooms, and 30 two-bedrooms) over six “micro-commercial” spaces; and, on an adjacent infill lot, a set of 18 three-story townhouses designed to be 80% more energy efficient than comparable structures built to code. Both parts of the project, which is being developed by San Francisco-based Domus Development, will be supplemented by rooftop solar power and solar hot water systems.

Called La Valentina, the project is emerging on a desolate corner lot that had been vacant for almost two decades – a location, one resident of the neighborhood told the Sacramento Press, that was dangerously derelict and seriously in need of redevelopment. The location does have a built-in advantage, however: it is a few steps away from the La Valentina/Alkali Flat station serving the Regional Transit District’s light rail system in Sacramento.

Erin Kelly, a project assistant at Domus, told GBA that the portion of the project that includes the townhouses, known as La Valentina North, features three-bedroom units ranging in size from 1,005 to 1,215 sq. ft. in both flat and townhouse-style configurations. The capacity of the solar power system for the entire complex is 38.4 kW. All La Valentina North units have been designed for net-zero-energy performance, Kelly added. Although Domus is not at liberty to disclose prices at this point, she noted that all units in the complex will be available for rent to tenants earning between 30% and 60% of the area median income.