The victims were 34-year-old Megan Keller and 29-year-old Cody Keller.
Investigators said they were found dead inside their Touby Road home around 8:30 a.m. on Nov. 8
Authorities said the deputies went to the home for a well-being check for the two victims.
A detective from the Wooster Police Department was concerned Megan and Cody did not show up for work at their jobs on Wednesday.
The sheriff's office said deputies were told there was a new coal burner installed in the home and they were worried it was malfunctioning.
Megan was a supervisor in Wooster and Cody worked for Gorman Rupp.
Investigators said deputies tried to open the door and could smell a rotten egg smell.
The Washington Fire Department said the levels were at 4,000.
The house was aired out so investigators could safely enter the home.