John Jones had collected items for more than 20 years
John Jones' house in Aberystwyth was so full that he built a network of tunnels so he could move around in it.
Four tonnes of rubbish had to be removed from the 62-year-old's bedroom before police could carry his body out through a window, the inquest was told.
Ceredigion coroner Peter Brunton recorded a verdict of accidental death.
The inquest in Aberystwyth was told Mr Jones, a widower who weighed 20 stone and had mobility problems, had collected rubbish for more than 20 years.
His garden and sheds at his home were packed full of rubbish, along with several garages which he had rented from Ceredigion Council.
Mr Jones' body was found in a bedroom at his home in September, after he had not been seen by his neighbours for some time.
Coroner Mr Brunton said it was likely some of the rubbish had fallen on Mr Jones and he had probably died from asphyxiation.
But pathologist Christopher Simpson told the inquest that the cause of death was unknown because the body was so badly decomposed.
Sgt Wyn Griffiths of Dyfed-Powys Police said Mr Jones was found under bags of rubbish.
He told the inquest that the body was carried out of a bedroom window, which had been entirely removed by fire fighters because the house was so packed full of items.
"Nobody could have entered the bedroom. There was some sort of tunnel system so he could climb through the house," added Sgt Griffiths.
"There were items up against the sides of the walls, in the hallways, bedrooms, landing and items hanging from the ceiling.
"The easiest way was to carry the body through the window."
Mr Brunton said Mr Jones was a "compulsive collector of rubbish".
"On the balance of probabilities, part of the rubbish that Mr Jones had accumulated in his bedroom collapsed on his body."