Ontario · Home health · checked September 28, 2026

Carbon monoxide testing and CO alarms in Oshawa

Carbon monoxide is odourless and can kill. Ontario's Fire Code requires CO alarms in existing homes that have a fuel-burning appliance, a fireplace or an attached garage: next to every sleeping area and, since January 1, 2026, on every storey as well.

A carbon monoxide alarm on an upstairs hallway wall outside the bedrooms at night

CO alarm rule

Required in existing homes

Natural gas heat

72%

Single-detached share

56%

Alarm cost

$40–$80 each

How Oshawa is built

Oshawa's houses by when they were built Ten house shapes, one for each tenth of Oshawa's 52,550 houses. Before 1961: 24%, 1961–1990: 43%, 1991–2000: 8%, 2001 or later: 25%. Older houses glow hotter.
  • Before 1961 24%
  • 1961–1990 43%
  • 1991–2000 8%
  • 2001 or later 25%
Each house stands for one in ten of Oshawa's 52,550 houses (single-detached, semi-detached, row and duplex), drawn by when it was built. The glow shows the usual pattern: older houses tend to be leakier and less insulated. Snowfall scales with heating degree-days. Sources: Statistics Canada 2021 Census (table 98-10-0233-01), NRCan HOT2000 climate data.

The rule in Ontario

Ontario's Fire Code requires CO alarms in existing homes that have a fuel-burning appliance, a fireplace or an attached garage: next to every sleeping area and, since January 1, 2026, on every storey as well.

Where CO alarms go: installation rules in Ontario

What the rules say about installing alarms:

  • Required in every home with a fuel-burning appliance, a fireplace or an attached garage, and since January 1, 2026 also in homes served by a forced-air fuel-burning appliance located outside the building.
  • Put an alarm next to each sleeping area and, since January 1, 2026, on every storey that has no sleeping area.
  • Hardwired, battery and plug-in alarms are all allowed.
  • The homeowner is responsible in an owner-occupied home, and the landlord in a rental.
  • For new houses, the National Building Code 2020 (Article 9.32.3.9) requires a CO alarm inside each bedroom or within 5 m outside each bedroom door when the home has a fuel-burning appliance or an attached garage, an alarm in any room with a solid-fuel-burning appliance (on or near the ceiling unless the maker's instructions say otherwise), and interconnected alarms in a house with a secondary suite.

CO sources in Oshawa homes

In the Oshawa area, the main heating energy is natural gas for 72% of households (Statistics Canada, 2023). Any fuel-burning appliance, fireplace or attached garage is a potential CO source.

Single-detached houses make up 56% of Oshawa's households; many have an attached garage, another reason to put an alarm near the door into the house.

What a CO check involves

  • Alarms next to sleeping areas and on every storey, tested monthly and replaced by their end-of-life date (usually 7 to 10 years).
  • Annual service of fuel-burning appliances by a licensed technician.
  • A combustion spillage test during an energy evaluation, which catches a venting problem before it produces CO.

Our carbon monoxide guide · Combustion safety testing in Oshawa

Communities served

Area guide for the surrounding region, with every town and hamlet listed: Durham Region area guide (Port Perry, Uxbridge, Brock and more).

Carbon monoxide testing in Oshawa: common questions

Are carbon monoxide alarms mandatory in Oshawa?

Ontario's Fire Code requires CO alarms in existing homes that have a fuel-burning appliance, a fireplace or an attached garage: next to every sleeping area and, since January 1, 2026, on every storey as well.

Where should CO alarms go in Ontario?

Required in every home with a fuel-burning appliance, a fireplace or an attached garage, and since January 1, 2026 also in homes served by a forced-air fuel-burning appliance located outside the building. Put an alarm next to each sleeping area and, since January 1, 2026, on every storey that has no sleeping area. For new houses, the National Building Code 2020 (Article 9.32.3.9) requires a CO alarm inside each bedroom or within 5 m outside each bedroom door when the home has a fuel-burning appliance or an attached garage, an alarm in any room with a solid-fuel-burning appliance (on or near the ceiling unless the maker's instructions say otherwise), and interconnected alarms in a house with a secondary suite.

How long do CO alarms last?

Most have an end-of-life date of 7 to 10 years printed on the unit; replace them by then even if they still beep when tested.

Carbon monoxide testing near Oshawa

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