Kyle Saville, 26, of no fixed address, was sentenced to 21 years with four years on licence for the attempted murder of Daniel Morley and the wounding with intent of Richard Price.
Saville was found guilty of the offences after the court heard how he had launched a prolonged and vicious attack on Mr Morley, only to be stopped when a police officer looked in through a window from the street.
Saville had been staying at Mr Morley’s address in Barnstaple when he carried out the attack.
DC David Browne said: “We are extremely pleased with the guilty verdict and today’s sentence which quite rightly reflects the severity of the offences.
“The evidence in this case shows that Saville carried out a brutal and sustained attack against two vulnerable members of the community who posed no real threat to him.
“He repeatedly struck them about the head and face, and asked a witness to check on one of the victims to see if “he was dead yet?” Saville then continued attacking him when he learned that he was still alive.
“Thanks to the professionalism and diligence of Police Sergeant Andy Lear, Saville was prevented from carrying out his intention to poor boiling hot water over Daniel Morley, who had already sustained life-threatening injuries by that time.
“The two victims will live with the effects of this crime for the rest of their lives. I would like to express my thanks and gratitude to everyone who assisted in the investigation, in what has been a particularly difficult trial for those directly involved.”