Home Battery Storage in Ontario: Backup, Savings and Trade-offs

Home batteries have become far more common in Ontario over the past few years, driven by storm-related outages, the Ultra-Low Overnight price plan and rebate programs. A battery can be a genuinely useful upgrade, but it is rarely a money-maker on its own. This guide explains what a battery can and cannot do, what it costs, and how to decide whether one makes sense for your home.

What a home battery actually does

A home battery stores electricity and releases it later. Most residential systems today use lithium iron phosphate (LFP) chemistry, which is more thermally stable and longer-lived than older lithium-ion types. A battery can serve three purposes:

Backup power. When the grid goes down, a properly configured battery isolates your home and keeps selected circuits running.
Rate shifting (arbitrage). Charge when electricity is cheap and discharge when it is expensive.
Solar self-consumption. Store midday solar surplus and use it in the evening instead of exporting it.

Note: Solar panels on their own do not keep your power on during an outage. Grid-tied inverters shut down automatically for line-worker safety. You need a battery plus backup-capable equipment, often called a gateway or automatic transfer switch.

Typical costs in 2026

Configuration	Usable capacity	Typical installed cost (estimate)
Single battery, critical-loads backup	10–13.5 kWh	$12,000–$17,000
Single battery, whole-home gateway	13–16 kWh	$14,000–$20,000
Two batteries, whole-home backup	26–30 kWh	$24,000–$35,000+
Standby generator (natural gas), for comparison	Unlimited while gas flows	Varies widely; get quotes

Costs rise if your main panel needs upgrading, if the battery must be installed far from the panel, or if a separate critical-loads subpanel is needed.

Backup power: sizing for an outage

For backup, think in terms of what you must keep running and for how long. A rough guide:

Load	Typical draw	Energy over 24 hours (estimate)
Fridge (modern ENERGY STAR)	100–200 W cycling	1.0–1.5 kWh
Gas furnace fan and controls	300–700 W while running	3–8 kWh in cold weather
Sump pump	800–1,000 W while running	0.5–3 kWh (varies widely)
Lights, internet, phone charging	100–300 W	1.5–3 kWh
Well pump	1,000–2,000 W while running	1–3 kWh

A single 13.5 kWh battery can usually keep essentials, including a gas furnace blower, running for one to two winter days. With solar recharging it, spring and summer outages can be ridden out for much longer. A battery will not run an electric furnace, electric baseboard heat or a heat pump for long; those loads can draw tens of kWh a day in an Ontario winter.

Rate shifting on Ultra-Low Overnight

The Ontario Energy Board's ULO plan, effective 1 November 2026, charges 3.7¢/kWh overnight (11 p.m.–7 a.m. every day) and 37.7¢/kWh on-peak (weekdays 4–9 p.m.). That roughly 34¢ spread is what makes batteries interesting.

Worked estimate. Suppose your home uses about 8 kWh during the weekday 4–9 p.m. window. A battery charges overnight and covers that load instead:

Grid cost avoided: 8 kWh × 37.7¢ = about $3.02 per weekday
Overnight charging cost (allowing about 10% round-trip losses): about 8.9 kWh × 3.7¢ = about $0.33
Net commodity saving: about $2.69 per weekday, or roughly $670 over 250 weekdays
After the 15.7% Ontario Electricity Rebate reduces what each kWh costs you: roughly $550–$600 a year

On a $15,000 battery that is a simple payback of about 25 years, longer than most battery warranties (commonly 10 years). With a $5,000 rebate, it is closer to 17–18 years. These are estimates; your evening usage, rate plan and battery efficiency drive the result. Check plan fit with our price plan calculator.

Tip: If you are not on ULO, rate shifting is worth much less. On Time-of-Use, the spread between on-peak (18.9¢) and off-peak (9.1¢) is under 10¢.

The HRS battery rebate and net metering

The Home Renovation Savings Program, jointly delivered by Save on Energy and Enbridge Gas, has offered up to $10,000 combined for rooftop solar plus battery storage, reported as up to $5,000 for each. According to program rules published in 2026, systems receiving this rebate operate as load displacement and cannot enrol in net metering for the life of the system. Electricity exported to the grid is not credited.

A battery reduces exports, which softens the impact, but it rarely eliminates them in summer. An analysis by The Atmospheric Fund (July 2026) argues many homeowners would be better off keeping net metering. We compare both routes with full assumptions in solar rebate vs. net metering. Confirm current terms on saveonenergy.ca (opens in a new tab) before committing.

Safety, permits and placement

ESA permit and inspection. Battery installation is electrical work and must be done by a Licensed Electrical Contractor under an Electrical Safety Authority permit. See esasafe.com (opens in a new tab).
Certified equipment. Look for systems certified for use in Canada and listed to recognized energy storage safety standards such as UL 9540 (ask the installer for documentation).
Location. Manufacturers set temperature limits. LFP batteries often cannot charge below about 0 °C without built-in heating, so unheated garages in Ontario winters need careful product selection. Follow clearance and fire-separation requirements.
LDC notification. A grid-connected battery, especially one paired with solar, generally needs approval from your local distribution company.
Insurance. Tell your home insurer.

Battery or generator?

For backup alone, a generator is usually cheaper per hour of protection. A natural gas standby generator can run for days in a long winter outage, while a battery is limited by its stored energy and solar recharging. Generators, however, need annual maintenance, produce noise and exhaust, and must be installed with a proper transfer switch; a gas-fired unit also involves a TSSA-registered gas contractor. Batteries are silent, switch over in a fraction of a second and can earn rate-shifting savings the rest of the year. Many rural homeowners with wells and sump pumps find a generator the more practical choice.

A quick decision checklist

You have frequent or long outages, a sump pump, a well, or medical equipment: a battery is easier to justify.
You are on ULO or willing to switch, and your evening usage is substantial: rate-shifting savings are meaningful.
You want maximum financial return on solar: net metering without a battery is usually the cheaper route.
You need backup for a few hours only, rarely: a portable power station or generator may be far cheaper.

Frequently asked questions

How long does a home battery last?

Most LFP home batteries are warrantied for about 10 years, often with a guarantee of around 60–70% of original capacity at the end. Many will last longer, but plan your economics on the warranty period.

Can I add a battery without solar?

Yes. A standalone battery can provide backup power and rate shifting on ULO. Confirm whether any rebate you are considering requires paired solar.

Can I charge my battery from the grid overnight and sell power back?

No. Net metering credits apply only to electricity generated by your renewable system, and Ontario homeowners cannot sell stored grid power back. Grid charging is used to shift your own consumption.

Will a battery run my heat pump during a winter outage?

Only briefly. A heat pump in cold weather can use 30–60 kWh or more per day. For winter backup in an all-electric home, consider a larger multi-battery system or a generator.