Firefighters were called to a property in Mid Devon after a carbon monoxide detector sounded.
They attended the house Ridgedown, Chittlehampton, Umberleigh just before 6am on Sunday.
A spokesman for the service said: "One fire fighting appliance from South Molton fire station and one fire fighting appliance from Barnstaple fire station attended reports of a carbon monoxide alarm sounding.
"Upon arrival, crews used their gas detector monitor to see the levels of carbon monoxide in the property.
"There was a positive reading but very minimal, crews used two breathing apparatus and one hose reel jet to examine the property."
