How long does it take to install a whole-home standby generator from start to finish in Ontario?

A whole-home standby generator installation in Ontario typically takes 4 to 12 weeks from first call to fully operational system — but the actual hands-on installation work is only 1 to 3 days. The bulk of that timeline is permits, utility coordination, and equipment lead times.

Here's how the process actually unfolds.

The Permit and Approval Phase (2–8 Weeks)

This is where most of the timeline lives, and it's non-negotiable in Ontario. A standby generator installation requires two separate permits: an ESA electrical permit for the transfer switch, wiring, and connection to your home's panel, and a TSSA (Technical Standards and Safety Authority) permit for the natural gas line connection. Your electrician handles the ESA side; a licensed gas fitter (often the same contractor if they hold both licences, or a separate HVAC/gas contractor) handles the TSSA side. Both permits must be applied for before work begins.

On top of permits, your local gas utility — Enbridge Gas for most of the GTA — needs to confirm that your existing gas service has sufficient capacity to supply the generator. A 16–22 kW standby unit draws significant gas volume, and if your service line is undersized or shared with high-demand appliances, Enbridge may need to upgrade the service. That coordination alone can add 2 to 4 weeks in busy seasons.

If your electrical panel is under 200A, you may also need a panel upgrade before the transfer switch can be properly installed, which adds another permit cycle and potentially Toronto Hydro coordination for a service entrance upgrade.

Equipment Lead Times (2–6 Weeks)

Generac, Kohler, and Briggs & Stratton are the dominant standby generator brands in the GTA market. In normal conditions, lead times run 2 to 4 weeks from order to delivery. After major ice storm events — and the GTA's 2013 ice storm is the textbook example — demand spikes dramatically and lead times can stretch to 8 to 12 weeks or longer. If you're ordering in the fall before winter, expect longer waits. This is one of the strongest arguments for not waiting until after a power outage to start the process.

The Actual Installation (1–3 Days)

Once permits are in hand and equipment is on site, the physical installation moves quickly. Day one typically covers the generator pad (a concrete or composite pad outside the home, set back from windows and doors per code), the transfer switch installation at the panel, and the electrical wiring. Day two covers the gas line connection and the control wiring between the generator and transfer switch. A properly sized 20 kW unit on a straightforward detached home in Mississauga or Markham can realistically be fully installed in two days by an experienced crew.

GTA-Specific Considerations

Setback requirements matter in Toronto and the inner suburbs. Generators must be positioned away from windows, doors, gas meters, and property lines — and in dense urban neighbourhoods with tight lots, finding a compliant location can require some creative planning. Condo and townhouse owners face additional hurdles: many condo corporations prohibit standby generators entirely, and even freehold townhomes in strata arrangements may have restrictions. Confirm with your property management before ordering equipment.

Seasonal timing is worth thinking about. The GTA's ice storm season runs roughly November through March. Ideally, you want your generator commissioned and tested before the first major ice event. Starting the process in August or September gives you the best chance of being operational before winter. Starting in November after the first outage means you're competing with every other homeowner who had the same idea.

ESA inspection happens after installation is complete. The inspector verifies the transfer switch installation, wiring methods, and code compliance. If the work passes, you receive a Certificate of Inspection — keep this permanently with your home records, as it's required documentation for insurance purposes and at resale.

Cost Snapshot

Budget $8,000 to $15,000 for a complete whole-home standby installation in the GTA, including the generator unit, automatic transfer switch, concrete pad, electrical work, gas connection, and both permits. Larger homes needing a 22 kW+ unit or a panel upgrade can push toward $18,000 to $22,000.

Hire a licensed electrician and a licensed gas fitter for this project — no exceptions. The transfer switch involves working directly with your main panel at full service amperage, and the gas connection carries its own serious risks. Both trades require separate permits and inspections. This is not a DIY project in any part.

Need help finding a licensed electrician for a generator installation? Toronto Electrical Repair can match you with local professionals through the Toronto Construction Network — browse the directory at torontoconstructionnetwork.com/directory?trade=electrical.