Home Backup Power Options in Ontario: Generator vs Battery

The main home backup power options in Ontario are a portable generator connected through a transfer switch, a permanently installed standby generator running on natural gas or propane, and a home battery, sometimes paired with solar. A portable generator is the cheapest way to keep essentials running; standby generators handle long outages automatically; batteries are quiet and clean but cover hours rather than days unless they can recharge.

This guide compares costs, run times and practical trade-offs, and covers the safety and permit rules that apply in Ontario.

Start with what you actually need to power

Backup sizing starts with a short list of essential loads, not the whole house. Typical running loads (estimates; check nameplates):

Load	Running watts (approx.)	Starting surge	Notes
Gas furnace blower and controls	400–800 W	Moderate	Without power, a gas furnace will not run
Sump pump (1/3–1/2 hp)	800–1,100 W	2–3 times running	Critical in spring and during storms
Fridge	100–200 W average	800–1,200 W	Cycles on and off
Chest freezer	50–150 W average	500–800 W
Well pump (240 V)	1,000–2,000 W	High	Rural homes
Lights (LED), internet, phone charging	100–300 W	Low
Cold-climate heat pump	2,000–5,000+ W	Varies	Often beyond small backup systems
Electric water heater, range, dryer	3,000–5,000 W each	Low	Usually excluded

A typical "essentials" list for a gas-heated home (furnace, fridge, freezer, sump pump, lights, internet) is roughly 1,500–2,500 W running with surge capacity for motor starts. That fits a mid-size portable generator or a single home battery. Homes heated with electricity or a heat pump need much more capacity in winter.

Estimate your needs with our backup power calculator.

Home backup power options compared

Option	Typical installed cost (estimate)	Run time	Best for
Portable power station (1–3 kWh)	$500–$3,000	A few hours for small loads	Phones, internet, a fridge for a while, CPAP
Portable generator (3,000–7,500 W) plus transfer switch or interlock	$1,500–$4,000 total	As long as you refuel	Essentials during occasional outages
Inverter generator (2,000–4,000 W)	$800–$3,000 plus connection	As long as you refuel	Quieter, cleaner power for electronics
Standby generator (natural gas or propane, 10–22 kW)	$10,000–$20,000+	Days, automatically	Frequent or long outages, medical needs, rural homes
Home battery (13–16 kWh)	$12,000–$20,000	Roughly 8–24 hours of essentials	Quiet, automatic, fume-free backup
Battery plus solar	Battery cost plus solar system	Can recharge on sunny days	Longer outages in spring to fall

Figures are typical 2026 ranges and vary with site conditions, brand and whether panel work is needed.

Portable generators: lowest cost, most hands-on

A portable generator is the most common backup in Ontario. To power household circuits safely, it must connect through one of:

• a manual transfer switch, which feeds selected circuits; or
• a generator interlock kit on the main panel, which physically prevents the main breaker and generator breaker from being on at the same time.

Either option requires an ESA permit and is best installed by a Licensed Electrical Contractor. Expect roughly $500–$1,500 for the connection, plus the generator itself.

Trade-offs: you must be home to start it, refuel it (a typical unit burns several litres of gasoline every few hours), and store fuel safely. Noise can bother neighbours. Dual-fuel models can run on propane, which stores better than gasoline.

Caution: Never run a generator inside your home, garage, shed or near windows and doors. Carbon monoxide can kill within minutes. Ontario requires working carbon monoxide alarms in homes with fuel-burning appliances or attached garages; test them before storm season.

Caution: Never plug a generator into a dryer or range outlet to "backfeed" the house. This can energize utility lines and seriously injure or kill line workers, and it can start fires.

Standby generators: automatic, but expensive

A standby generator is permanently installed outside, connected to your natural gas or propane supply and wired through an automatic transfer switch. When the grid goes down, it starts within seconds.

• Gas work requires a TSSA-registered contractor; the gas meter and piping must be able to supply the generator alongside your furnace and water heater. Enbridge may need to assess meter capacity.
• Electrical work requires an ESA permit.
• Maintenance: annual service and periodic self-tests are needed.
• Running cost: a 10–20 kW unit can burn several cubic metres of natural gas per hour at moderate load, so a multi-day outage has a real fuel cost.

Standby generators suit rural homes with frequent outages, homes with well and sump pumps, and households with medical equipment that cannot be interrupted.

Home batteries: quiet and automatic

A home battery, typically 10–16 kWh, switches over automatically during an outage and powers a backed-up subpanel or, with larger systems, the whole home. Advantages: silence, no fuel, no fumes and no maintenance. Limits: a single battery covers essentials for roughly 8–24 hours depending on loads, and it cannot run large electric heating for long.

Batteries can also save money on Ultra-Low Overnight or Time-of-Use plans by charging off-peak and discharging during expensive hours. Our home battery storage guide covers sizing and economics in depth.

If you are considering solar with a battery, note that the Home Renovation Savings Program's combined solar and battery rebate has a catch: systems receiving it operate as load displacement and cannot enrol in net metering for the life of the system. Our solar rebate vs net metering comparison explains the trade-off, and our solar hub covers the basics.

What about vehicle-to-home?

Some electric vehicles can supply power to a home through bidirectional charging equipment. In 2026 this remains limited to specific vehicles, chargers and approved interconnection equipment. If it interests you, confirm compatibility and ESA approval requirements before buying.

Which option fits your situation?

Your situation	Likely best fit
Outages are rare and short; tight budget	Portable power station or portable generator with interlock
Gas heat; want furnace, fridge and sump during outages	Portable generator with transfer switch, or one battery
Frequent multi-day rural outages, well pump	Standby generator
Medical equipment, or no one home to manage a generator	Standby generator or battery
Heat pump or electric heat, long winter outages	Standby generator sized for heating, or keep a backup heat source
Want quiet backup plus bill savings	Battery, possibly with solar

Backup power checklist

1. List essential loads and estimate running and surge watts.
2. Decide how long you need to cover: hours, a day, or several days.
3. Get quotes that include the transfer switch or interlock and the ESA permit.
4. For gas generators, confirm gas supply capacity with a TSSA-registered contractor.
5. Install and test carbon monoxide and smoke alarms.
6. Plan for a heat-loss scenario: see our power outage preparedness guide.

Frequently asked questions

What size generator do I need to run a furnace?

A gas furnace's blower and controls typically need 400–800 W. Many furnaces are sensitive to "dirty" power, so an inverter generator or a properly sized conventional unit with stable output is recommended. Add the fridge and sump pump, and a 3,000–5,000 W generator is common.

Can a battery keep a heat pump running?

Briefly. A heat pump in cold weather can draw several kilowatts, which drains a single 13–16 kWh battery quickly. Plan for a backup heat source or a larger system if winter outages are your main concern.

Do I need a permit for a transfer switch?

Yes. Connecting any generator or battery to your home's wiring is electrical work that requires an ESA permit in Ontario.

Is a portable power station enough?

For phones, internet, lights and a fridge for a few hours, often yes. It will not run a furnace or sump pump for long.