What Should I Do If I Smell Gas or a CO Alarm Sounds?
Gas odor and a CO alarm are not troubleshooting questions. Get people and pets away before thinking about the furnace.
Do not re-enter until emergency professionals say it is safe.
Leave first
Take people and pets outside. Do not stay inside to find the source.
Avoid ignition
Do not flip switches, use a phone inside, light a match, or operate the thermostat.
Call from outside
Use 911 or the gas utility. Arrange HVAC inspection only after the home is cleared.
Gas odor near a furnace
The source cannot be safely identified by opening a panel. Leave, avoid sparks, and call from outside.
Do not turn the furnace on to see whether the smell clears or shut a valve unless instructed.
- Move outside.
- Avoid switches and flames.
- Call from a safe location.
When a CO alarm sounds
A CO alarm is a reason to leave even if the furnace looks normal. Carbon monoxide cannot be judged by smell.
After clearance, HVAC inspection may look at combustion, venting, heat-exchanger condition, and operation.
- Do not silence the alarm and stay.
- Tell responders which alarm sounded.
- Do not restart fuel-burning equipment until cleared.
The HVAC boundary
The repair company can inspect equipment after the safety event. It does not replace the fire department, gas utility, or emergency responder.
When you later arrange HVAC gas-leak service, share what responders found.
- Treat odor and alarms as safety information.
- Keep equipment off if instructed.
- Ask what was tested before repair.
Questions homeowners ask next
Should I open windows before leaving?
No. Do not stay inside to ventilate or investigate. Leave first and call from outside.
Can an HVAC company handle a gas leak?
Emergency responders or the utility handle the immediate response. HVAC inspection may follow after clearance.
What if the alarm stops?
Still leave and report it. An alarm that stops does not prove the home is safe.