What Is the Best Whole-House Generator for a Power Outage?

Ice storms, wind events, and grid failures in Toronto and the GTA can leave a home without power for hours or days. A whole-house generator kicks on automatically and runs the whole home from natural gas or propane. This guide covers the top brands, sizing, fuel choices, and what installation involves in Ontario.

What is the best whole-house generator for a power outage?

For most Ontario homes, the Generac Guardian series is the most common and cost-effective whole-house generator. Kohler and Cummins offer premium alternatives with longer warranties and better reliability records. The right size for a typical 3,000 sq ft GTA home is 18–22 kW, running on natural gas from the existing utility supply. Installation with automatic transfer switch typically runs $8,000–$16,000 CAD in the GTA.

Top brands compared

• Generac: largest market share, extensive dealer network, models 7.5–26 kW. Guardian series is the residential standard. Good value, 10-year warranty options.
• Kohler: premium build quality, quieter operation, 5-year warranty standard. Higher price point, smaller dealer network.
• Cummins: commercial-grade construction adapted for residential. Very reliable, 5-year warranty. Higher cost.
• Briggs & Stratton: budget option in smaller sizes. Fewer features, shorter warranty.
• Champion: emerging brand, competitive pricing in mid-range sizes.

Sizing for your GTA home

Whole-house sizing depends on total connected load and what you want to run during an outage.

• 7–10 kW: essentials only (furnace, fridge, some lighting, one or two circuits). Suitable for a 1,000–1,500 sq ft home.
• 14–17 kW: most circuits, AC on lower stage, no dryer. Typical 2,000 sq ft home.
• 20–24 kW: whole house including central AC, dryer, water heater. Standard for 2,500–3,500 sq ft homes.
• 26 kW+: larger homes, or homes with EV charging and heat pump plus AC.

Load-shedding options let smaller generators handle larger homes by dropping non-essential loads automatically. See how to install a transfer switch.

Fuel: natural gas vs propane

• Natural gas: preferred for GTA homes with existing gas service. No refuelling, unlimited runtime, lower operating cost. Most Toronto homes have natural gas available.
• Propane: for homes without natural gas (rural, cottage country). Requires an on-site propane tank. Longer refuelling cycle but higher energy density.
• Diesel: uncommon in residential. Long shelf life, high energy density, but noisy and messy.

Most GTA installs are natural gas, tapped from the existing utility line.

What installation involves in Ontario

1. Load calc to size the generator and transfer switch.
2. Site survey for generator placement (setback from windows and property lines).
3. Concrete pad or composite base installation.
4. Gas line extension by a licensed gas fitter (natural gas or propane).
5. Automatic transfer switch install at the electrical panel by a licensed electrician.
6. Electrical wiring between generator and transfer switch.
7. ESA notification and inspection.
8. TSSA gas inspection.
9. Commissioning and testing.

Timeline: typically 1–3 days on site plus permit and inspection lead time.

Cost breakdown for the GTA

• Generator unit (18–22 kW): $5,000–$8,000 CAD.
• Automatic transfer switch: $800–$2,000 CAD.
• Installation (electrical + gas + concrete): $3,000–$7,000 CAD depending on gas line distance and site prep.
• Permits (ESA + TSSA): included in contractor quote typically.
• Total installed: $8,000–$16,000+ CAD.
• Annual maintenance: $300–$500 CAD.

Smart features to consider

• Wi-Fi monitoring (test status, alerts, self-diagnostics remotely).
• Load management (works with the transfer switch to shed loads if generator undersized).
• Weekly self-test that runs the engine briefly for reliability.
• Cold-weather kits for reliable winter starts.
• Sound-attenuation enclosures for quieter operation.

Ontario-specific considerations

• Winter operation: cold-weather kit and battery warmer are worth the small extra cost.
• Municipal noise bylaws: check local rules on generator noise levels.
• Setback requirements: typically 1.5–3 metres from windows and property lines.
• Utility interconnection: generators with automatic transfer isolate from the grid safely.
• TSSA gas certification: required for any natural gas or propane connection.

Expert tip from our ESA-licensed electricians

The single biggest sizing mistake we see in GTA generator installs is buying too small to save money upfront. A homeowner picks a 14 kW to save $2,000 on a 20 kW, then loses the AC and dryer during summer outages. Cost-benefit: size the generator for what you actually want to run comfortably, not for the emergency minimum. In a mid-sized GTA home, 20–22 kW is the sweet spot. It also gives you headroom for future electrification (heat pump, EV) without a second install.

Frequently Asked Questions

How long can a whole-house generator run?

Indefinitely on natural gas. Propane depends on tank size (typically 1–5 days on a 500-gallon tank).

Do I need a permit for a generator?

Yes. Both ESA electrical and TSSA gas notifications are required.

Are Generac generators reliable?

Generally yes. Some early models had issues, but modern Guardians have improved reliability significantly.

Can I install a generator myself?

No. Gas connection requires TSSA-certified fitter; electrical requires licensed contractor.

Do generators need maintenance?

Yes. Annual service plus oil changes and battery checks. Most brands recommend certified service.

Related reading from ezsmart.ca

• How to Install a Transfer Switch for a Portable Generator
• What to Do in a Power Outage
• Why Do I Need a Whole-House Surge Protector?
• How to Calculate Home Electrical Load Capacity
• Why Does Power Come Right Back On?

Contact us

Interested in a whole-house generator for a Toronto or GTA home? Call ezsmart at 416-838-9006 or use our contact page. An ESA-licensed electrician will assess your home, coordinate the gas fitter, and manage the whole install.