What electrical work is needed for a heated garage and how much does 240-volt heater installation cost in Ottawa?

Heating a garage in Ottawa requires electrical work that goes beyond simply plugging in a heater, and the cost to set up a proper 240-volt garage heating circuit runs between $800 and $2,500 depending on your existing electrical setup and the heater type you choose.

Most effective garage heaters for Ottawa winters run on 240 volts because they produce significantly more heat than 120-volt portable units. A 240-volt electric garage heater draws between 20 and 40 amps depending on the wattage, and that requires a dedicated circuit from your panel with appropriately sized wire, a breaker, and proper connections at the heater location.

The most common options for electric garage heat in Ottawa are ceiling-mounted forced air heaters and infrared radiant heaters. Ceiling-mounted forced air units like the Fahrenheat or Dimplex models range from 4,000 to 7,500 watts, cost $200 to $600 for the unit, and heat a two-car garage effectively in most conditions. Infrared heaters mount high on the wall or ceiling, heat objects directly rather than the air, and work well in garages where the door opens frequently because they warm you and your work surface rather than the air that escapes. Infrared units cost $300 to $800 and draw similar amperage.

The electrical installation for a 240-volt garage heater involves running a dedicated circuit from your panel to the heater location. For an attached garage where the panel is on the other side of the wall, this is relatively simple and costs $800 to $1,500 including the ESA permit, a 30-amp double-pole breaker, 10 AWG wire run, and the heater hookup. For a detached garage that already has a sub-panel, adding a 240-volt heater circuit from the sub-panel costs $400 to $800. If your detached garage does not have a sub-panel yet, you need to factor in that full project cost first.

A 5,000-watt heater on a 240-volt circuit draws about 21 amps, so it runs on a 30-amp circuit with 10 AWG wire. A 7,500-watt heater draws about 31 amps and needs a 40-amp circuit with 8 AWG wire. Your electrician sizes the circuit based on the specific heater you choose, and this must be determined before the installation begins because the wire gauge and breaker size are specific to the load.

The Ontario Electrical Safety Code requires a disconnect switch for a hardwired heater that is within sight of the unit. This is typically a small disconnect box mounted on the wall near the heater and adds $50 to $100 to the installation. The ESA inspector will check for this during the inspection.

For running costs, a 5,000-watt electric heater running four hours per day through Ottawa's heating season of roughly October through April costs approximately $550 to $700 per year at current Hydro Ottawa rates. A 7,500-watt unit under the same conditions costs $800 to $1,050. These numbers assume you are on Hydro Ottawa's time-of-use pricing and running the heater mostly during off-peak hours. Running the heater during on-peak hours significantly increases the cost.

Insulation Matters More Than Heater Size

Before investing in a large heater, make sure your garage is reasonably insulated. An uninsulated garage in Ottawa loses heat so quickly that even a powerful heater struggles to maintain a comfortable temperature when it is minus 25 outside. Insulating the garage door with a kit at $100 to $200, insulating walls to R-12 or better, and sealing gaps around the door frame make a dramatic difference in how effectively any heater performs. A well-insulated two-car garage can often get by with a 4,000 to 5,000-watt heater, while an uninsulated garage of the same size might need 7,500 watts and still feel cold on the worst Ottawa winter days.

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• Demontigny Carpentry