Foul play was ruled out after a post-mortem revealed he died from hypothermia and alcohol consumption. Gardai are not treating his death as suspicious.
It has since been established that Mr Lis had been drinking with friends on Monday night, but at some stage left the house and went outside.
When they went looking for him later, they found his body and immediately raised the alarm. He was carried into the house but the emergency services declared him dead when they arrived shortly before 2am.
Neighbours said Mr Lis had been living in the area for over a year but did not mix with other residents. He was known to drink heavily.
"We don't know who he is but if it's who I think, he looked about 50 but was only about 35," said local resident and musician Robert O'Connor.
"I used to see him in the laneway at the back of the houses that leads to Tesco, he'd be coming or going with a bag of cans," he added.
"He would look like he had been hard at the drink.
"I remember once he was trying to hurry me along the queue in Tesco because he wanted to pay for his beers and go.
"We didn't know anything about the man dying until we saw the garda tape at the door yesterday morning," said one woman who lives on the other side of Church Avenue.
Mr Lis's death brings to four the number of people who have died in the last three months due to the combination of sub-zero temperatures and alcohol or drug consumption.
Last month, the bodies of John Glennon (67) and Debbie McEvoy (63), a former nurse from Newry, Co Down, were found huddled together at a flat in Drumalee Court in Stoneybatter, north of the city centre.
Although they both suffered from health problems, they died from hypothermia.
Alcoholism was cited as a factor in the death of Mr Glennon, who had just one electric heater after switching off the gas supply several years ago.
The heater was not on in the flat when the deaths occurred. It was also discovered that Mr Glennon and Ms McEvoy had not eaten for days.
On December 8, the body of Paul Doyle (33), from Bray, Co Wicklow, was found outside the doorway of a Tesco Express supermarket in the town early in the morning.
A post-mortem revealed he also died from hypothermia.
Mr Doyle, who suffered from mental health and addiction problems, had been sleeping rough for more than a year.