Adam Edwards torched his bed with a lighter which spread to the carpet and forced staff and other residents to flee from Heathcotes, on Belle Vue Road, Wakefield.
The 21-year-old admitted a charge of arson being reckless as to whether life was endangered at Leeds Crown Court.
Samuel Ponniah, prosecuting, told the court that Edwards had been joining in with group activities at the home on the morning of October 8 last year before he went back to his room at around at 11.30am.
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Minutes later he come running out and shouting that there was a fire in his room.
The head of services tried to use an extinguisher on the flames but was unable to bring it under control so the fire service was called.
They determined that the fire had been started deliberately and a cigarette lighter was found in the room.
Edwards had been banned from having a lighter because of previous fire-related incidents at the home.
He claimed he dropped the lighter and it ignited the blanket on his bed.
The court was told that two psychiatric reports were carried out on Edwards, and both found him not to be suffering from any mental disorders, but had a low intelligence.
James Littlehales, mitigating, said Edwards had an "extremely difficult upbringing and is extremely vulnerable".
The court was told that Edwards was unable to live on his own, so was living at the home that caters for people with special needs.
Edwards was heard sobbing as he appeared in court over the video link from prison.
The judge, Recorder Darren Preston handed him two years' jail and said: "You were mucking around with a lighter, which you should not have had because of previous incidents involving fire.
"People could have been injured or killed."
He is expected to serve half of the sentence before being released on licence, but having already spent nine months on remand, he will serve around another three months behind bars.