Have you ever walked out of your house or apartment with the thought that you might have left the burner on? It's a paralyzing feeling, and it's one that firefighter Peter Thorpe is all too familiar with. "People lose their lives every year because they accidentally leave their stove on," Thorpe says. "Every four and a half minutes, there is a kitchen fire." Another staggering statistic? Thorpe notes that one in 22 apartments will have a kitchen fire every year.

That's why Thorpe created FireAvert, a device that responds to the sound of a smoke alarm and automatically turns off electric ranges or ovens that were cooking forgotten-about food. He pitched the product in season 7 of Shark Tank, emphasizing the devastating frequency of these tragedies to the sharks.

"Everyone has a grandma or is a busy parent themselves," Thorpe says. "People lose their lives every year because they accidentally leave their stove on. We're making a difference — we're saving lives."

When Thrope walked into the tank, he was seeking $300,000 for 7 percent equity. But at the time, he had sold 60 percent of FireAvert to a partner for $50,000, leaving him with only 30 percent equity, which made the sharks wary of investing.

Thorpe did end up making a deal with Lori Greiner, who offered $300,000 for a 10 percent royalty to $400,000, plus 10 percent equity. While ultimately the parties didn't end up closing on that deal, Thorpe says his business is doing better than ever.

But perhaps the most significant development since FireAvert was featured in the tank is its partnership with one of the most recognizable names in hospitality."Marriott Vacations Worldwide is putting FireAvert into all of their vacation rentals and timeshares," Thorpe shares. "That's big."

Although the deal fell through with Greiner, the exposure the company got Shark Tank worked out well for the Utah-based business, which saves its an average customer anywhere from $30,000 to $100,000 a year, according to Thorpe.

"We travel quite a bit, and when we were getting on a plane to come home, some ladies recognized me and said, 'You're on Shark Tank — the whole plane wants to talk to you,'" Thorpe says. "We go to trade shows every month, and people recognize us from the show. They come up to you and want your picture, or they want to buy the product just because they saw it on Shark Tank."

Watch Shark Tank, weeknights starting at 7P ET on CNBC.