BOULDER – Populus LLC provides consulting in sustainable design, working with hundreds of clients who want to improve the energy efficiency of their homes, often requesting to take them to “zero energy” – homes that produce as much energy as they consume.

In this area in particular, people care deeply about energy efficiency as it relates to the environment, said Laura Hutchings, chief executive of Populus, which was founded by her husband, David Neiger.

Ultimately, that’s not the main reason people make home-energy improvements. Energy security – having a buffer to the volatility of energy costs – is what resonates everywhere, she said. And that’s not what most residential energy efficiency firms focus on.

“Our approach to the market has been very unique,” Hutchings said. “Our approach is people first, buildings second. We approach it as a relationship rather than a transaction. One of the challenges that has existed in this market is that oftentimes program implementation has not been customer focused. A lot of our growth is fueled by this people-centric model.”

Populus has developed what may be the go-to model for communities or utilities seeking to improve residential energy efficiency, a big reason the company now is running programs for the city of Boulder and Boulder County, and for the Denver Energy Challenge. Hutchings said a custom approach for potential clients of these programs led to success in recruiting participation, which fed the company’s success.

As a result, Populus’ annual revenue grew 663 percent from $397,570 in 2010 to $3 million in 2012, placing it No. 1 on the Boulder County Business Report’s Mercury 100 list of fastest-growing private companies based in Boulder and Broomfield counties reporting annual revenue of more than $2 million.

Eighty percent of the growth is from implementation of the municipal programs.

Unlike similar programs, which run energy diagnostics and develop a list of potential items for homeowners that could reduce energy costs, Hutchings’ advisers dig deeper, adding items that might add another dimension such as increased comfort. Populus also helps secure multiple bids from qualified contractors.

The company started on a much different model, helping the city of Boulder develop SmartRegs, which promotes energy efficiency in rental property, the first such ordinance in the nation. Populus’ income growth in the immediate future is tied to such large–scale community programs like those in New Mexico and Idaho and from national programs.

“A lot of national competitors are going to start doing what we’re doing,” she said. “We are looking for strategic partners. All options are on the table.”