Jan. 2, 2008 Green tech is playing an increasingly prominent role at Honeywell. The company has seen its profits double over the past five years, thanks in large part to an exploding market for energy-efficient technologies, according to CEO Roger Fradin.

Fradin tells Investor's Business Daily that green technologies, such as automated control systems for building thermostats, have fueled "a real nice turnaround" for the company, which has seen annual sales jump from $6.5 billion to about $13 billion.

"[Green products make up] somewhere between 30% and 50% of our business," he says. "Call it 40% of the demand for our products and solutions is driven by energy efficiency, in one form or another."

Fradin says the biggest seller is a time-controlled thermostat that can save up to 30% in building energy costs. The boost in demand has driven the company to make key innovations, such as an iPhone-like touch-screen user interface for thermostat systems.

Other top-selling green products include sensors that help car and airplane engines run more efficiently, and controls that reduce energy use from manufacturing operations.