“My CO alarm went off.”
If your CO alarm is sounding, right now
Get everyone out of the building and into fresh air. Do not stop to investigate, open windows, or find the source.
From outside, call 911 or your fire department. If anyone is drowsy, confused, nauseated, has a headache, or has collapsed, treat it as a medical emergency and say so on the call.
Do not go back inside until emergency services tell you it is safe. Once it is, call us at (847) 729-9190 and we will come and find the cause.
There is no version of this where a phone call or a video walkthrough replaces evacuating and calling for help. Video guidance is useful for a dripping line or a thermostat question, never for this.
What carbon monoxide is
Carbon monoxide is a product of incomplete combustion — a fuel-burning appliance not getting the air it needs, or not venting the way it should. It is colourless and odourless, which is the whole danger: your senses give you nothing, and the early symptoms read as flu.
Where it comes from in a house
- A furnace or boiler with a cracked heat exchanger
- A blocked, disconnected or corroded flue or vent
- A water heater or other appliance backdrafting instead of venting outside
- An attached garage where an engine has run, with return-duct leakage pulling that air into the house
- Anything fuel-burning operated indoors that was never meant to be
Low-level monitors and why they differ from alarms
A standard residential CO alarm is designed to sound at concentrations and exposure times tied to acute danger. It is deliberately slow to sound at lower levels.
A low-level monitor reports concentrations well below that threshold — useful because chronic low exposure can make people unwell without ever tripping a standard alarm. One is included with the Gold membership.
Combustion testing
A combustion analyser samples the flue gases of a fuel-burning appliance and reports what the combustion is actually doing. It is how a venting or combustion problem is found before it becomes an emergency, and it is part of a proper maintenance visit rather than an add-on.