A Calgary secondary suite requires hardwired, interconnected smoke and carbon monoxide alarms across both the suite and the main dwelling. Interconnection means an alarm triggering in one unit sounds in the other. Standalone battery alarms do not meet the requirement.
This is the requirement people most often think they have already met, and most often have not. Battery alarms from a hardware store do not satisfy it. The word that matters is interconnected.
What interconnected means
It means that when an alarm triggers anywhere, every alarm sounds. An alarm going off in the basement suite must also sound upstairs, and the reverse.
Think about why. A fire starting in the suite at two in the morning is useless information to the family asleep upstairs if the only alarm sounding is behind a closed, fire rated door two floors below them. Interconnection is what carries the warning across the separation that is otherwise doing its job of keeping things apart.
Both alarms, both units
You need smoke alarms and carbon monoxide alarms, and the requirement covers both the suite and the main dwelling. A suite with its own alarms that are isolated from the rest of the house does not meet the standard.
Carbon monoxide matters particularly in a suite, because you have added gas appliances, altered mechanical arrangements and created a sleeping area in a part of the house that was not previously used that way.
Hardwired, not battery
Interconnection is normally achieved by hardwiring, which is why this is electrical work planned during rough in rather than something fitted at the end. The alarms sit on the electrical plan alongside the circuits.
If you are retrofitting into an existing suite, wireless interconnected systems exist, but whether a particular product satisfies the requirement in your situation is a question for the inspector, not for a product page. We work that out before quoting.
Planning a suite? Alarms, circuits and fire separation are decided together at drawing stage. Free consultation, free 2D structure design, fixed quote. Call 587 439 5191.
What the City incentive lists
The City of Calgary Secondary Suite Incentive Program has listed hardwired smoke and carbon monoxide alarms at up to $1,000. It is a reimbursement paid after the work is complete and the suite is registered, not funding provided up front, and new applications were placed on a waitlist as of 24 June 2026. Confirm the current position with the City.
Where it sits in the inspection
Alarms are checked at final inspection, along with EGRESS WINDOW openings and ventilation. By then the electrical work behind them has already been inspected at rough in. If the wiring was never run, this is not a defect you fix on the day.
That sequencing is the reason suites fail inspection on items that look small. We list the usual causes in why basement suites fail inspection in Calgary.
Key facts
- Alarms must be interconnected, so one triggering anywhere sounds every alarm in both units.
- Both smoke and carbon monoxide alarms are required, covering the suite and the main dwelling.
- Interconnection is normally achieved by hardwiring, making it electrical work planned at rough in.
- Standalone battery powered alarms do not satisfy the requirement.
- The City of Calgary Secondary Suite Incentive has listed hardwired smoke and CO alarms at up to $1,000.
- Alarms are verified at final inspection, but the wiring behind them is inspected earlier at rough in.
Frequently asked
Do battery smoke alarms meet the requirement?
No. The requirement is interconnection, so that an alarm sounding in one unit sounds in the other. That is normally achieved by hardwiring, which is planned as part of the electrical rough in.
Do I need alarms in the main house as well as the suite?
Yes. The requirement covers both dwelling units. A suite with alarms isolated from the rest of the house does not meet the standard.
Why are carbon monoxide alarms so important in a suite?
A suite adds gas appliances, changes the mechanical arrangement and creates sleeping space in a part of the house not previously used that way. All three raise the reason for CO detection.
Can wireless interconnected alarms be used in a retrofit?
Wireless interconnected systems exist, but whether a specific product satisfies the requirement in your situation is a question for the inspector. We establish that before quoting rather than assuming.
Does the City incentive cover alarms?
The programme has listed hardwired smoke and carbon monoxide alarms at up to $1,000. It is a reimbursement after the suite is built and registered, and new applications were waitlisted as of 24 June 2026.
