Do I need a dedicated circuit for a bathroom exhaust fan with a built-in heater?

Yes, a bathroom exhaust fan with a built-in heater almost always requires a dedicated electrical circuit. Unlike a standard exhaust fan that draws only 30–80 watts, a fan-heater combo unit draws 1,000–1,500 watts (some models up to 2,000 watts) when the heater is operating. This is a significant electrical load that cannot safely share a circuit with other bathroom fixtures.

A standard bathroom circuit in most GTA homes is a 15-amp, 120-volt circuit with a maximum capacity of 1,800 watts. A fan-heater combo drawing 1,500 watts would consume over 80% of that circuit's capacity on its own — leaving almost no room for the vanity lights, GFCI outlets, and other devices sharing the same circuit. Running the heater on an overloaded circuit will trip the breaker repeatedly, which is both annoying and a sign that the circuit is undersized for the load. The Ontario Electrical Safety Code and the Canadian Electrical Code require that circuits not be loaded beyond 80% of their rated capacity for continuous loads.

Your electrician will typically install a dedicated 20-amp circuit from the electrical panel to the fan-heater unit. This provides 2,400 watts of capacity at 120 volts — more than enough for even the highest-wattage fan-heater combos with comfortable headroom. The circuit must include GFCI protection, either at the breaker panel (a GFCI breaker) or at the first outlet on the circuit, as required for all bathroom electrical circuits in Ontario.

Installation Considerations for GTA Homes

The practical challenge in many Toronto homes is running the new dedicated circuit from the electrical panel to the bathroom ceiling. In older Toronto homes — the post-war bungalows, two-storeys, and split-levels common across the GTA — the electrical panel may be in the basement, and running a new circuit to a main-floor or second-floor bathroom means fishing wire through walls and ceilings. This is manageable for a licensed electrician but adds labour time and cost compared to a simple fan swap.

In GTA condos, adding a dedicated circuit can be more complicated. Condo electrical panels have limited space for new breakers, and running new wiring through concrete ceilings and walls requires different techniques than wood-frame houses. Discuss this with your electrician early in the renovation planning process — if your condo panel is full, a sub-panel or tandem breaker may be needed.

Cost and Product Selection

Fan-heater combo units range from $150–$500 for the unit itself, depending on features. Basic models offer a fan and radiant heater with separate switches. Mid-range models add a built-in light. Premium models from manufacturers like Panasonic and Broan include a fan, heater, LED light, and night light with a multi-function wall switch or wireless remote control.

Installation cost for a fan-heater combo with a new dedicated circuit runs $500–$1,200 by a licensed GTA electrician, including the new circuit from the panel, GFCI protection, switch installation, and ESA inspection. If you are replacing an existing fan with a fan-heater combo and a dedicated circuit already exists (or can be easily extended), the cost drops to $200–$500 for the swap.

This is an especially worthwhile upgrade for GTA bathrooms without in-floor heating. A ceiling-mounted heater warms the bathroom quickly on cold Toronto winter mornings — stepping out of the shower into a heated bathroom is a significant comfort upgrade. The heater also helps dry the bathroom faster after showers, reducing moisture-related issues like peeling paint and mould growth. An electrical permit and ESA inspection are required for the new circuit installation.