After looking around for home energy efficiency investments for years, venture capital company General Catalyst decided to buy a majority stake in ClearResult, a sign of confidence in a relatively small, low-tech industry.

General Catalyst said it has bought a majority stake in Austin, Texas-based ClearResult, which works mainly with utilities to design commercial and residential building-efficiency programs. General Catalyst managing director Hemant Taneja today declined to say how much it invested.

A thermal imaging camera, one of the tools used by home efficiency professionals. That blue spot in the corner means there&39's a gap in the wall insulation.

Traditionally, venture capitalists have steered clear of service-oriented businesses, favoring instead entrepreneurs with unique technology which offers the potential for rapid growth. For example, Next Step Living, a residential home efficiency company, ended up raising money from wealthy individual "angel" investors after not finding interest with VCs.

The appeal of ClearResult is the management team and the belief that home energy efficiency has the potential to grow far more, Taneja said. In addition to energy audits, companies can retrofit heating and cooling equipment or do on-site electricity generation, for example.

"We really believe this space has a lot of headroom to it. For all the talk about how energy efficiency is low-hanging fruit, it's a pretty small industry," he said. "I think it's going to see a lot more sophistication."

What's needed is for companies to make home efficiency services more "turn key" by offering financing for efficiency investments and ways to measure energy savings, Taneja said.

Many building-efficiency service companies are small operations, but some large companies will emerge from the field, predicted Lyndon Rive, the CEO of SolarCity, which is a solar installer that bought a home efficiency services company last year.

"Five years ago in solar things were very similar. There were hundreds of mom-and-pop companies and no established brand names," he said. "We see the same thing happening in energy efficiency--over time, consolidation will occur to get economies of scale."

Taneja told the Boston Globe that with the investment in ClearResult, General Catalyst hopes to expand its presence from 15 to 50 states.