Clarum Communities has been incorporating solar energy and solar thermal hot water heating into its homes since the 1990s.

That’s one reason the northern-California homebuilder was at the top of the list when the United States Green Building Council went to issue its annual awards this year. Clarum won production builder of the year for it Cambridge Plaza condominiums in Palo Alto, Calif.

The three-story condos sit above commercial space and each come equipped with a 2.8-kilowatt solar photovoltaic system and a high-end two-tank solar thermal hot water heater and back-up pump.

The project runs entirely on electric with no natural gas.

“We were at about 50 percent of the energy use coming from solar,” said Clarum founder John Suppes. “But we didn’t factor the electric cars into that.”

He said each of the four units came equipped with an electric vehicle charger. And one of the new owners already has an electric vehicle.

The project is also within walking distance of public transportation, something Suppes looks for when building a sustainable project like Cambridge.

The chargers are a feature that Suppes might need to start building into more of his homes as electric vehicles become more common.

Suppes founded Clarum on the notion that homes needed to be more energy efficient and he’s long found the sun to be a key ingredient in building better houses.

“We’ve been doing solar on large-scale projects since the mid 1990s,” he said.

The first was an apartment complex. He’s incorporated solar energy into many other projects since then.

Clarum builds a lot of urban mixed-use projects with commercial space on the ground level and condos or townhomes above. But the company also builds single-family homes in the suburbs around San Francisco.

Suppes said he recently finished a demonstration home, a single-family residence, that is a certified passive home. It’s a net-zero project.

“It’s a pretty amazing house,” he said.