What size generator do I need to run my whole house?

The size generator you need depends on your home's electrical load, but most Ottawa homes require a 15-20kW generator for essential circuits or 20-30kW for whole-house backup. To determine the exact size, you'll need a licensed electrician to calculate your home's actual electrical demand.

Understanding Generator Sizing

Generator sizing isn't just about your panel's amperage - it's about calculating your actual electrical load. A 200-amp panel doesn't mean you need a 200-amp generator, since you rarely use all circuits simultaneously. Your electrician will perform a load calculation considering your home's square footage, heating system, air conditioning, major appliances, and lighting.

For a typical Ottawa home, here's what different generator sizes can handle:

15-20kW generators can power essential circuits including furnace, refrigerator, some lights, and a few outlets. This covers heating, food preservation, and basic lighting during outages - adequate for most families' emergency needs.

20-25kW generators add capacity for more circuits, potentially including your hot water heater, garage door opener, and additional outlets throughout the house. This size works well for homes with gas heating and moderate electrical demands.

25-30kW generators approach true whole-house backup, powering most circuits including electric heating (if applicable), multiple appliances, and maintaining normal electrical usage patterns during outages.

Ottawa-Specific Considerations

In Ontario, generator installation requires an ESA permit and inspection. The generator must be installed by a licensed electrician and connected through a proper transfer switch - never backfeed through a regular outlet, which is illegal and deadly. ESA requires generators be positioned at least 1.5 meters from windows, doors, and air intakes.

Natural gas generators are popular in Ottawa since they connect to your existing Enbridge gas line, providing unlimited runtime. Propane generators work well for homes without gas service but require tank refills. Standby generators automatically start during outages and typically restore power within 10-20 seconds.

Installation costs in Ottawa typically range from $8,000-$15,000 including the generator, transfer switch, electrical connections, gas line work, and permits. Higher-capacity units and complex installations cost more.

Next Steps

Contact a licensed electrician to perform a proper load calculation for your specific home. They'll assess your electrical panel, major appliances, and usage patterns to recommend the right generator size. This ensures you get adequate backup power without overpaying for unnecessary capacity.

For generator installation and sizing consultation, Electrical Ottawa's licensed electricians can evaluate your home's needs and handle the complete installation process, including ESA permits and inspections.

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Find a Licensed Electrician

Electrical Ottawa connects you with vetted, ESA-licensed electricians from the Ottawa Construction Network:Ottawa Electrical Contractors:

• Mike Fuller Electric
• Ottawa Electric
• CLX Electric