October 8, 2026

By EB Horsman & Son

Smoke alarms and carbon monoxide alarms are simple life-safety devices, but determining what you need can get complicated.

If you are building or renovating a home, do you need a smoke alarm in every bedroom? What about the basement? Can a combination smoke and carbon monoxide alarm meet both requirements? Requirements can become more complex for secondary suites, apartments, condominiums and commercial buildings.

This guide covers smoke alarms, carbon monoxide alarms and fire alarm systems in British Columbia, with practical information for homeowners, electricians, contractors, builders, developers and property managers.

Where Are Smoke Alarms Required in a New BC House?

The BC Building Code 2024 requires smoke alarms in dwelling units in several key locations.

1. Every Storey

At least one smoke alarm is required on every storey of the dwelling unit, including the basement. A house with a basement, main floor and second floor therefore needs smoke detection on all three levels.

2. Every Sleeping Room

On a storey containing sleeping rooms, a smoke alarm is required inside each sleeping room. If a home has three bedrooms, that means three individual bedroom alarms.

3. Outside the Sleeping Rooms

Another smoke alarm is required between the sleeping rooms and the remainder of the storey. Where a hallway serves the bedrooms, the smoke alarm is typically installed in the hallway. This is why the common rule of thumb of “one smoke alarm per floor” is not enough for a new BC house.

How Many Smoke Alarms Do You Need in a New BC Home?

There isn’t one number that applies to every house.

Under the BC Building Code 2024, smoke alarms in a dwelling unit must be installed so there is at least:

One smoke alarm on every storey, including basements
One smoke alarm in each sleeping room
One smoke alarm between the sleeping rooms and the remainder of the storey
An alarm in the hallway when a hallway serves the sleeping rooms

The layout and number of bedrooms therefore determine the number of alarms required.

For example, a two-storey home with a basement and three bedrooms on the second floor could require at least six smoke alarms:

Basement: 1
Main floor: 1
Bedroom 1: 1
Bedroom 2: 1
Bedroom 3: 1
Second-floor hallway: 1

The actual number depends on the home’s design and the requirements applicable to the project.

What About Carbon Monoxide Alarms in BC?

Carbon monoxide protection serves a different purpose from smoke detection. Carbon monoxide, commonly called CO, is a colourless and odourless gas that can be produced when fuels such as natural gas, propane, gasoline, oil or wood do not burn completely.

Potential sources in and around a home include gas furnaces, boilers, water heaters, fireplaces, wood stoves, generators and vehicles operating in an attached garage. Because carbon monoxide cannot be seen or smelled, occupants cannot rely on their senses to know when it is present.

A standard smoke alarm does not detect carbon monoxide unless it is specifically designed and certified as a combination smoke and CO alarm.

When Are Carbon Monoxide Alarms Required in BC?

The BC Building Code contains CO alarm requirements for residential buildings where there is a potential carbon monoxide source associated with the building.

This can include circumstances involving:

Fuel-burning appliances
Solid-fuel-burning appliances
Storage garages

The exact requirements depend on the building and the location of the potential CO source.

For a new home with a gas furnace, gas fireplace or attached garage, CO protection should therefore be considered as part of the building design from the beginning.

Can You Use a Combination Smoke and Carbon Monoxide Alarm?

Yes. A combination smoke and carbon monoxide alarm can provide both forms of detection in a single device when the product is certified for the application and installed in a location that satisfies both requirements.

However, a combination alarm does not reduce the number of required smoke-alarm locations elsewhere in the house. For example, if smoke alarms are required in three bedrooms but CO protection is required in the hallway outside those bedrooms, installing a combination smoke and CO alarm in the hallway does not eliminate the need for the three bedroom smoke alarms.

Combination devices are best thought of as providing two forms of detection at one location, rather than replacing every other required alarm in the house.

What Changes With a Secondary Suite?

The BC Building Code contains specific provisions for smoke alarms in houses with secondary suites. Depending on the construction, alarms may need to communicate between dwelling units and common spaces, and the requirements can be affected by the fire-resistance rating of the separation between the units and whether the building is sprinklered.

For this reason, adding a basement suite should not be approached as simply installing another smoke alarm downstairs. The alarm system needs to be considered together with the fire separation and other life-safety requirements for the suite.

Do Smoke Alarms Have to Be Hardwired and Interconnected?

For typical new construction supplied with electricity, smoke alarms are generally required to be permanently connected to an electrical circuit and have a battery backup. There cannot be a disconnect switch between the overcurrent device and the smoke alarm.

Where more than one smoke alarm is required within a dwelling unit, the required alarms must also be interconnected so that when one activates, the others sound. If a fire begins in the basement while occupants are sleeping upstairs, interconnection helps provide warning throughout the home.

This is an important difference between building a new home and simply replacing an alarm in an older house. Do not assume that a standalone battery-operated alarm will meet new-construction requirements.

What Changes in an Apartment or Condominium Building?

Multi-unit residential buildings introduce an important distinction between the protection provided inside an individual dwelling unit and the building’s main fire alarm system.

An apartment or condominium unit may contain smoke alarms or permitted smoke detectors to protect the occupants of that suite. At the same time, the building may have a separate fire alarm system serving common spaces and other required locations. Depending on the design, that system may include a fire alarm control panel, smoke and heat detectors, manual pull stations, horns, strobes, annunciators and supervisory equipment.

A smoke alarm inside an apartment and a smoke detector connected to the building’s fire alarm system may look similar, but they can perform different functions. The approved building and fire alarm design determines how the devices are intended to operate.

What Fire Alarm Standards Apply in BC?

Commercial and larger multi-unit projects can involve several Canadian ULC standards. CAN/ULC-S524 addresses fire alarm system installation, CAN/ULC-S537 addresses verification, and CAN/ULC-S536 addresses ongoing inspection and testing.

The applicable edition and requirements should always be confirmed for the specific project.

Does the BC Building Code Apply in Vancouver?

The City of Vancouver follows its own 2025 Vancouver Building By-law (VBBL), based on the 2024 BC Building Code with Vancouver-specific requirements.

For dwelling units, smoke alarms are required on every storey, including basements, as well as in each sleeping room and between sleeping rooms and the rest of the storey. Required alarms are generally hardwired with battery backup and interconnected where more than one alarm is required.

Carbon monoxide protection is required when a dwelling unit has an attached garage or fuel-fired appliance, or when it shares a wall or floor with a parking garage or a service room containing fuel-fired equipment. Where CO protection is required, alarms must be installed either inside each bedroom or outside each bedroom within 5 m of the bedroom door, measured along corridors and through doorways.

For complete requirements, including existing buildings, renovations and multi-unit properties, refer to the City of Vancouver’s current guidance, click here.

Additional Resources

For more detailed information on smoke alarms, carbon monoxide alarms, fire alarm systems and fire safety requirements in British Columbia, refer to these resources:

BC Building Code 2024 – Requirements for new construction, including fire alarm and detection systems.
BC Fire Code 2024 – Fire safety requirements for existing and occupied buildings.
BC Building & Fire Code Bulletins – Useful for interpretations, changes and clarifications to current code requirement

Choosing Smoke and Carbon Monoxide Alarms

At EB Horsman & Son, we can help you choose the right smoke and carbon monoxide alarms for your application, whether you’re working on a new build, renovation or replacement. We carry a range of Kidde smoke and carbon monoxide alarms, with options for hardwired, battery backup, combination detection and interconnected applications.

Contact your local EB Horsman branch or contact us below today.

Shop Kidde Solutions at EBH

Contact EBH

Source