BRAINTREE, Mass. -- A dog is being credited with saving her owner's life, after the woman's home filled with smoke and carbon monoxide.

NewsCenter 5's Jim Boyd reported that Rose Cappola, 91, said she stays up late and sleeps late.

"I'm a very sound sleeper," she said.

But on Wednesday morning, Cappola was rousted from that sound sleep at about 9:30 a.m.

"The dog started barking and barking. And I says, 'What are you barking for?' So, I get up and he ran in here and I came in after him and I says, 'Oh my god, there's smoke all over the house,'" Cappola said.

Cappola said she checked the basement and found the smoke coming from a malfunctioning furnace. She turned the furnace off and called the fire department.

Firefighters convinced Cappola to go to the hospital, where doctors said she had been exposed to carbon monoxide fumes, but was all right. Firefighters said with a few more minutes of exposure, the outcome could have been much worse.

Cappola said she shudders to think of what would have happened if she didn't have Josie to wake her.

"She woke me up. I says, 'If it wasn't for her, I probably would have been dead,'" Cappola said.

Cappola said her smoke alarm did not go off until after she woke up and she didn't have a carbon monoxide detector installed in the house. Her nephew bought one for her on Wednesday.

Meanwhile, she said she is thankful her friend, Josie, a 4-year-old terrier mix who was there to look out for her.

"I don't know what to do without her," Cappola said.