At at time when a friendly female voice can help smartphone users schedule a haircut and help them find the nearest sushi restaurant, a wallet-sized thermostat with a limited vocabulary and monotone male voice hardly seems like a miracle. But for the thousands of visually impaired people who own a talking thermostat, Harry Cohen is something of a hero.

"Frankly, I can't imagine living without one," said Ron Milliman, a Kentucky-based retired professor of marketing and the owner of three talking thermostats, which allow him to control the temperatures of his house and vacation home even though he's visually impaired. With just a touch of an up or down arrow, a voice tells Milliman the temp he's selected and whether he's requesting heat or air conditioning. "They allow me to independently control the heating and A/C units in my houses."

When Cohen started selling those thermostats more than a decade ago, starting a company wasn't high on his bucket list. He had just retired from a 23-year career as an engineer and sales manager for Honeywell, the nation's largest thermostat manufacturer. During his travels for that company, people regularly asked for a thermostat that could be used by people who are visually impaired. Cohen asked Honeywell the same question.

" 'There aren't enough blind people to make it profitable,' " he was told. "If they can't sell millions of widgets, they don't want to be in the business; these are high-volume companies."

Ultimately, though, it was a gentle nudge from his wife — several months into his retirement — that got the business started.

"My wife gave me an ultimatum: find something to do, or move out of the house," he said.

So Cohen started a company named for his grandson, Ezra, and in 2000 started looking for thermostat manufacturers that might let Cohen adapt their product. There were only two, and he decided to work with a company in New Orleans that manufactures the VIP thermostat in China. Cohen worked with that company to modify the software, enabling it to offer scripted messages at the touch of a button. He made several other enhancements, including easier-to-use On and Off switches, in three models.

By 2003, Cohen launched the VIP Series, which looks like any other thermostat and retails for $199.50. There's an easy-to-read display, an up and down arrow and several buttons for other functions, including "heat" and "cool." When you push a button, a male voice (not Cohen's) describes the request: "Cool, 73 degrees," for example.

Cohen said that reprogramming the software took very little effort, and that while he could have activated it with voice commands, he chose not to because ambient noises (music, barking dogs and other common household sounds) could inadvertently reset the temperature.

Milliman, an active member in the American Council of the Blind, said that he'd waited years for such a product.

"It always seems like we [visually impaired people] are running behind the bus," he said.

Despite Milliman's enthusiasm, Cohen is tapping into a relatively small market. Cohen won't reveal his sales figures, but he said that he dominates the industry and that sales have been stable.

"I don't do a million dollars in sales, but I'm selling enough to keep me happy. And I give a lot of these away," he said. "For me, this is a keep-busy business."

He's kept the company small in no small part because he can operate the Internet-based, two-person company from his Golden Valley home, and from anywhere in the world. That makes spending a couple of months during the winter in a sunny place a lot easier.

While Cohen isn't much one for bragging, there is one little factoid that he isn't shy about sharing: He's sold units to buyers in 49 of 50 states.

"People don't use them in Hawaii," he said. "Because the weather is so perfect."