Two adults and two children escaped from their house at Longland Close in Goodleigh in the early hours of this morning after a pottery kiln started leaking carbon monoxide.
Two fire engines from Barnstaple were called to the address around 12.30am after receiving reports of a carbon monoxide alarm sounding.
When the crews arrived all four occupants had evacuated the house.
Fire fighters tracked the leak to an electric pottery kiln and ventilated the house to expel any remaining gas.
Crew manager Wayne Keenan said: "We think it was the clay inside the kiln which had been giving off carbon monoxide but we cannot be 100 per cent sure.
"It was very fortunate that the owners of the house had installed a carbon monoxide detector.
"They had all been in bed at the time but fortunately the alarm woke them all up and allowed them to get out of the house safely.
"We would advise anyone with any similar equipment such as a kiln, gas boiler, or open fire to install a carbon monoxide detctor. They can save lives."