← Electrical Advice & Planning
Plan smoke and carbon monoxide alarms as part of the renovation, not as a finishing detail. Room layouts, sleeping areas, storeys and the existing alarm arrangement can all affect the review. Identify the requirements and equipment before ceilings and walls are closed.
Smoke alarms and CO alarms detect different hazards. A combination unit includes both functions, but it still needs suitable placement, power and compatibility for the installation.
Review the existing locations first
Ontario’s homeowner guidance requires working smoke alarms on every storey and outside sleeping areas. New construction and particular renovation work may carry additional requirements, so that general rule is not a complete design for every project.
Prepare a floor plan showing bedrooms, halls, stairs and the alarms already present. Tell the contractor about a new bedroom, basement accommodation or changed room use.
Include Ontario’s 2026 CO requirements
For homes with a fuel-burning appliance, fireplace or attached garage, working CO alarms are required adjacent to each sleeping area and, effective January 1, 2026, on every storey, including those without sleeping areas.
Condominiums, apartments and other building arrangements have additional conditions that require review. Toronto Fire Services provides guidance for those situations. Do not assume that a rule for a detached house describes every multi-unit property.
Check replacement dates and product instructions
Record each alarm’s model, manufacture date and replacement instructions. Ontario advises replacing smoke alarms every ten years according to the manufacturer’s instructions; CO alarm replacement follows the manufacturer’s specified life.
A working test button is not a reason to retain an alarm beyond its prescribed replacement date. Keep the instructions and note the next replacement date when new equipment is installed.
Hardwired and interconnected systems need compatibility checks
Before replacing one device, establish how it is powered and whether it connects to other alarms. A similar plug or matching appearance does not prove compatibility.
Have the installer verify the manufacturer’s permitted arrangement. Include adapters, backup power and any interconnected devices in the review. Building fire-alarm equipment is a separate system and should not be altered as though it were an ordinary household alarm.
| Planning item | What to establish |
|---|---|
| Locations | Storeys, sleeping areas and project requirements. |
| Device type | Smoke, CO or combination equipment. |
| Power and interconnection | Existing system and compatible replacements. |
| Service life | Manufacture date and required replacement timing. |
| Renovation staging | Protection during work and final commissioning. |
Maintain protection during the renovation
Discuss dust-producing work and temporary arrangements with the project team. Alarms should not simply be disconnected and forgotten while the home remains occupied.
Follow product instructions for cleaning and testing. Ontario advises testing smoke and CO alarms at least monthly. Include testing and an explanation of normal indicators and warning signals at handover.
Respond appropriately to an alarm
If a smoke alarm signals a possible fire, leave and call 911. If a CO alarm sounds or CO exposure is suspected, move everyone to fresh air and call 911. Do not stay inside to search for the source or treat an emergency alarm as an ordinary maintenance chirp.
For a non-emergency chirp, follow the exact product’s instructions for battery, fault or end-of-life indications. If unsure whether the signal indicates an emergency, prioritize leaving and seeking emergency assistance.
Common questions
Can one combination unit cover the whole home?
No. Required locations still need to be addressed.
Should replacement happen before renovation finishes?
Plan the arrangement early so any wiring and mounting provisions can be coordinated with construction.
Explore Electric FX smoke and CO alarm installation or request an alarm review.
Further reading: Ontario home fire safety; Toronto Fire Services CO alarm requirements.