Where they belong
BC’s fire safety guidance is a smoke alarm inside every bedroom, outside each sleeping area and on every storey, including the basement, mounted on the ceiling or high on a wall and kept away from the kitchen. Interconnected alarms, where one sounds and they all sound, are best.
Any home with a fuel-burning appliance, a fireplace or an attached garage should have carbon monoxide alarms on every storey and outside each sleeping area. A home with a secondary suite needs alarms in each unit, and current practice is for the smoke and CO alarms in both units to be interconnected so they sound together.
How long they last
Replace smoke alarms when they’re 10 years old; the manufacture date is printed on the alarm. Replace carbon monoxide alarms on the schedule the manufacturer gives. An alarm with no readable date should be treated as past it. Press the test button on every alarm once a month, and replace 9-volt batteries at least once a year.
Older homes
Many older homes were built before bedroom alarms, interconnection or CO alarms were expected, and the alarms that are there are often past their date. These weren’t required when the house was built, but they are worthwhile safety upgrades. Hard-wired alarms should be replaced or added by a licensed electrician; battery and plug-in alarms you can install yourself.
What to do
- Before subject removal: note how many alarms will need replacing or adding.
- On possession: test every alarm, replace any past its date, and add CO alarms if the home has gas or wood heat or an attached garage.
- Every month: press the test button.
- With your household: make sure everyone knows what each alarm sounds like and how to get out.
What our inspection covers
We note where smoke and CO alarms are present and where they’re missing, their type and, where we can read it, their age, and the report says where alarms belong in that home. A home inspection doesn’t confirm that each sensor responds to smoke or carbon monoxide, so test every alarm yourself when you move in.
Moving into an older home? Book an inspection and we’ll list what needs adding.
Reviewed October 26, 2026 by Nick Hawley, Watch House Inspections. General information, not advice about a particular home.