Can I legally install a gas fireplace in my Ottawa bathroom and what are the Ontario ventilation requirements?

Gas fireplaces can be legally installed in bathrooms in Ontario, but the requirements are strict and the installation is significantly more complex than a standard living room installation — and frankly, most Ottawa bathrooms are not well-suited for it without substantial modifications.

The core legal requirement is that all gas fireplace work must be performed by a TSSA-licensed gas fitter — this applies everywhere in your home, and a bathroom installation is no exception. There is no scenario where this is DIY territory. Beyond the gas fitting requirement, a bathroom installation triggers additional Ontario Building Code provisions around ventilation, moisture management, and clearances to combustibles that make this a multi-trade project.

Ventilation Is the Central Challenge

Ontario Building Code requires that a direct-vent gas fireplace — the only type you should be considering for a bathroom — have its sealed combustion air intake and exhaust vent routed to the exterior. Direct-vent units draw outside air for combustion and exhaust through a co-axial (pipe-within-a-pipe) system, meaning they are completely sealed from the room and do not consume bathroom air or release combustion gases indoors. This is non-negotiable for a bathroom application. B-vent units are not appropriate for bathrooms, and ventless gas fireplaces are restricted under the Ontario Building Code and should never be considered for any indoor space in Ottawa, let alone a bathroom.

The practical challenge is that your bathroom's existing exhaust fan ventilation — which handles moisture from showers and baths — is entirely separate from the fireplace venting system. You will need a dedicated exterior penetration for the direct-vent termination, which must be located away from windows, doors, gas meters, and air intakes per TSSA clearance requirements. In an Ottawa winter, the termination point must also be positioned to prevent ice buildup from exhaust condensation blocking the vent — a real concern when temperatures drop to -25°C or below.

Clearances to combustibles are another significant constraint. Bathroom cabinetry, vanities, towel bars, and wall finishes must all maintain the manufacturer-specified clearances from the fireplace unit. Bathrooms are often tightly dimensioned spaces, and meeting clearance requirements while keeping the fireplace in a logical position can require custom millwork or structural changes.

Moisture is the third major factor. Bathrooms generate substantial humidity, and while a direct-vent fireplace is sealed from the room, the surrounding installation — framing, drywall, tile — must be appropriate for a wet environment. Your contractor will need to coordinate the fireplace rough-in with appropriate moisture-resistant materials and ensure the hearth area is properly waterproofed.

From a cost standpoint, a bathroom gas fireplace installation in Ottawa runs $5,000 to $10,000 or more depending on the complexity of the vent routing, whether a new gas line needs to be run to the bathroom, and any structural or finishing work required. A new gas line run to a bathroom location typically adds $500 to $1,500 on its own.

A building permit from the City of Ottawa is required, and the TSSA-licensed gas fitter must tag the completed installation with a compliance label. If you are in a heritage-designated neighbourhood, check with the City's heritage planning office before committing to any exterior vent penetration that would be visible from the street.

If you are seriously considering this project, browsing fireplace contractors through the Ottawa Construction Network directory at justynrookcontracting.com/directory is a good starting point — look specifically for contractors experienced with direct-vent installations in non-standard locations, as not every installer has done bathroom work before.