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Generator vs Home Battery in Ontario (2026): Hours of Backup, the Well Pump Starting Surge, Winter, Cost per Outage, Solar Plus Battery and the Rebate Rules
Electrical & Lighting
Generator or Battery: One Runs as Long as the Fuel Lasts, the Other Runs as Long as the Battery Lasts, and January Does Not Care Which You Bought
A battery is quiet, starts instantly and needs no fuel. A generator is noisy, needs propane or gas and a yearly service, and keeps going for days. Which one is right depends on how long your outages last, what has to keep running, and whether you have solar. This page puts real numbers on hours of backup, the starting surge that catches batteries out, and what each costs per outage.
The numbers
13.5 kWhone Tesla Powerwall 3
$19,000one Powerwall 3 installed, default
$13,00022 kW standby generator installed, default
$0rebate for a battery bought only for backup
| Backup option | Installed | Default or note |
|---|---|---|
| Tesla Powerwall 3, 13.5 kWh | $15,500 to $24,000 | $19,000 |
| Enphase IQ 5P, per 5 kWh module | about $4,400 to $4,500 | modules stack |
| FranklinWH aPower 2 | about $13,500 | one source only |
| Standby generator 14 to 18 kW | $8,500 to $13,000 | |
| Standby generator 20 to 26 kW | $11,000 to $18,000 | $13,000 (22 kW) |
| Portable generator connection: inlet and interlock | $700 to $1,200 | $950; generator extra |
Researched ranges from Ontario installers and Canadian price guides. HST is 13 percent on top. Fuel for a generator and a propane tank are extra.
Why Ontario prices are all over the map: for one Powerwall 3, the sources we checked ran from $15,500 at a Toronto electrical contractor to $24,000 before HST at an Ontario solar installer. That is $8,500 apart for the same box. Some prices appear to include a new gateway, a subpanel for the backed-up circuits and the ESA and utility paperwork; some are the battery bolted to the wall. Generators spread the same way: a Barrie contractor at $11,000 to $16,000 for a 22 kW against a dealer’s $10,500 to $12,500. Budget $19,000 for one battery and $13,000 for a 22 kW generator, and get two or three quotes on the same written scope.
How Long a Battery Really Lasts
A battery is a gas tank, not a gas station. Here is a typical rural house’s essential loads for a day, using typical figures, not your nameplates:
| Load | Typical running watts | Use per day | kWh a day |
|---|---|---|---|
| Fridge | 150 to 300 | runs about a third of the time | 1.5 |
| Chest freezer | similar, check the nameplate | 1.0 | |
| 1/2 hp well pump | about 1,000 | about an hour in total | 1.0 |
| Sump pump, 1/3 hp, spring thaw | about 800 | about an hour in total | 0.8 |
| Lights, internet, phones, TV | 1.5 | ||
| Summer essentials | 5.8 | ||
| Furnace blower, January | 500 to 800 | 600 W, half the day | 7.2 |
| Winter essentials, fuel-fired furnace | 13.0 |
Typical figures for illustration. A boiler’s controls and circulators typically run 150 to 300 W and are easier on a battery than a furnace blower.
So one 13.5 kWh battery carries the summer essentials for a bit over two days, and the January essentials for about one. Do not plan on running it to zero, either. Recharging in an outage needs solar, and a December panel under snow is a decorative roof.
And the battery does not heat the house. A furnace still needs its propane or gas. A heat pump on battery is a few hours at best. Electric heat is out of the question.
The Well Pump Decides the Inverter
A 1/2 hp submersible well pump typically runs at about 1,000 W and needs 2,000 to 3,000 W to start. A 1 hp pump runs at about 1,500 to 2,000 W and needs 4,000 to 6,000 W to start. A sump pump at 1/3 hp runs about 800 and starts at 1,500 to 2,500. The fridge, 150 to 300 running, wants about 1,200 for a moment.
A generator handles a start by slowing down for a second and recovering. A battery inverter has a hard limit on starting current, and if the pump asks for more, the inverter trips and you have a dark house with a full battery. So before buying, check the inverter’s rated starting current against the pump’s nameplate, and ask the installer to put it in writing. Some installers add a soft starter to the pump; that is their call and the pump maker’s. The well water page covers the pump itself.
Cost per Outage, and Doing Both
Take a 72-hour ice storm in January. The 22 kW generator at $13,000 runs through it on about 590 to 700 L of propane at half load, going by Generac’s published spec sheets, and everything stays on. One Powerwall at $19,000 covers about the first 24 hours of winter essentials, then the house goes dark and cold. Two Powerwalls cover about two days, and the two-unit prices we found were well over $25,000. For a four-hour summer storm, the battery is silent and you never notice; the generator starts, runs, and burns fuel the whole time.
Plenty of people do both: a battery for the short outages and the quiet, and a portable generator on an inlet and interlock, $950 plus the generator, for the long ones. That costs less than a standby and a battery together.
The rebate changes the battery maths only if you are adding new solar too. Home Renovation Savings pays $300 per kWh up to $5,000, at most 50 percent of the cost, and only for a battery paired with a new solar system; one 13.5 kWh battery works out to $4,050. A battery bought only for backup gets nothing. Taking the rebate also means no net-metering agreement: the system must be load displacement, for the house’s own use. Get written pre-approval from the program and your utility before buying, and do not count the money until it arrives. The solar grid connection page explains the connection side.
What Makes Sense in a Rural House
- Give every rural house a plan for a generator connection, at least an inlet and interlock or a transfer switch, done by the licensed electrical contractor under an ESA notification. On an ICF house the sleeve goes in before the pour.
- If outages here last days, buy fuel, not kWh. A standby or a portable on an inlet carries a well, a sump and a furnace for as long as there is propane.
- If you are putting on solar anyway, a battery makes sense, sized for the essentials and checked against the pump start.
- A tight house buys you time. A well-built ICF house has a small heat loss, so a dead furnace takes much longer to turn into a cold house; the ICFhome.ca houses are built that way. A leaky farmhouse in January is a problem by breakfast.
For the full rural outage list, see the rural power outage page, and for the generator line by line, the standby generator cost page.
Questions people ask
How long will a Powerwall run my house?
One 13.5 kWh Powerwall 3 runs typical summer essentials, fridge, freezer, well, sump and lights, for a bit over two days, and the same with a furnace blower in January for about one. Central air, electric heat or a heat pump empty it in hours.
Can a home battery run a well pump?
Often, but check first. A 1 hp submersible pump typically needs 4,000 to 6,000 W to start, and a battery inverter has a fixed starting limit. Compare the inverter’s starting current with the pump nameplate before you buy.
Is there a rebate for a home battery in Ontario?
Only with new solar. Home Renovation Savings pays $300 per kWh up to $5,000, at most half the cost, for a battery paired with a new solar system, with written pre-approval first and no net metering. A battery for backup alone gets nothing.
Which is cheaper, a generator or a battery?
For long outages, a generator: about $13,000 for a 22 kW that runs for days on fuel, against about $19,000 for one battery that runs about a day in winter. The cheapest real backup is a portable generator on an inlet and interlock, about $950 plus the generator.
See the hours and the cost for your own loads
The generator and battery sizing calculator takes your well pump, sump, furnace and fridge, checks the starting surge, and gives the generator size, the battery hours and the installed cost of each, side by side. If you already have quotes, the $99 review reads up to three and tells you whether the inverter was checked against your pump.
Sources and further reading
- ESA: generator safety: transfer devices, the notification for a permanent connection, and never running a generator indoors.
- Home Renovation Savings: solar and battery storage: the per-kW and per-kWh rebates, the pairing rule for batteries, pre-approval and the net-metering exclusion.
- Ontario Electrical Safety Code: ESA on the 2024 (29th) edition in force since May 1, 2025, and what changed for houses, EV loads and energy storage.
