The explosion in the small municipality in the canton of Aargau happened at 2:15, ripping apart the row house and setting it ablaze.
"The bang was incredibly loud," one neighbor told 20 Minuten Online.
Over 100 firefighters were sent to the scene and spent several hours getting the fire under control.
"There was debris everywhere," said police spokesman Roland Pfister. "The facades and windows of the surrounding houses were damaged."
After extinguishing the blaze, firefighters found the body of a man inside the ruins, presumed after a preliminary investigation to be that of the house's 56-year-old owner.
Police said they are not ruling out the possibility that the explosion was set off deliberately.
"We found several gas canisters inside the house," said Pfister. "The explosion was so massive that it couldn't have a been a result of fireworks," he added, nor was it connected to the mains gas supply.
August 1 was Switzerland's national holiday, when many people set off fireworks.
The man's wife was not in the house at the time of the explosion, but with her parents on holiday. According to neighbors, the couple had been fighting.
No other people were injured in the incident.
The destroyed building stood in the middle of a row of three houses, and police will check the stability of those structures before allowing residents to return.
Damages from the explosion are estimated at over one million Swiss francs.