Firefighters were called to the scene at 7.35pm on Wednesday after toxic gas filled the living room of the home in Barr Crescent, Clydebank, West Dunbartonshire, and set off the carbon monoxide detector.
They worked to clear gas from the property and helped five adults and two children who were suffering from the effects of gas inhalation.
Paramedics provided medical treatment and the seven people were taken for precautionary check-ups at hospitals in Glasgow.
Station commander Joe McKay said: "This incident was caused by a faulty gas fire that issued toxic gas into the living room. "
The Scottish Fire and Rescue Service said that over the past year more than 330 people have been injured and four people killed as a result of gas-related incidents across the UK, with one in five homes in Scotland thought to have an unsafe gas appliance.
Mr McKay said: "Gas is a silent killer and people should have a carbon monoxide detector in any room containing a boiler or fuel burning appliance, including gas fires and paraffin heaters. The early symptoms include tiredness, dizziness, chest pains and nausea, so people suffering from gas inhalation and CO poisoning are often unaware their lives are in danger.
"Heating and cooking appliances fuelled by gas, coal, smokeless fuels, wood and oil are a danger if they are poorly installed, incorrectly used, inadequately ventilated, or if they are not properly and regularly maintained."
He advised anyone using gas heating or appliances to ensure that their devices are regularly serviced and maintained by a Gas Safe registered engineer.