Misconception 1: "A Battery Will Power My Entire Home for Days"
Only if you size it for that, and most people don't. You can set up a battery for whole-home backup, but the more electricity your home uses, the faster it drains.
Most residential batteries hold about 10–15 kWh of usable energy. For comparison, an average Ontario home can easily use 20 kWh of electricity per day or more.
A 15 kWh battery can:
- Run critical loads — a fridge, internet, lights and a furnace fan — for a day or more.
- Run a home with high electricity use for only a few hours.
So the question is not "Can a battery power my home?" It's "Which loads do I need to power, and for how long?"
Misconception 2: "I'll Use the Battery for Backup and Save Money with Load Shifting"
You can do both — partly. Charging overnight at Ultra-Low Overnight (ULO) rates and discharging when electricity is expensive does cut your hydro bill. The trade-off: a battery that cycles every day may be low when the power goes out.
Option 1: Maximize financial savings (load shifting)
The battery charges overnight, when electricity is cheapest under Ontario's ULO pricing, and discharges during higher-priced hours. You buy less of the expensive daytime power.
Benefits
- Lower hydro bills
- More financial value from the battery
- Shorter payback periodThe length of time it takes for hydro bill savings to equal the upfront cost of a solar system.
Drawbacks
- The battery may be low when an outage hits
- Less backup power in an emergency
- Daily cycling wears the battery down faster
Option 2: Maximize backup availability
The battery stays full, ready for an outage at any time. You give up daily savings, so the whole charge is there when the grid goes down.
Benefits
- Maximum energy available when an outage hits
- More peace of mind during storms and grid disruptions
- Fewer charge-discharge cycles, which slows battery wear
Drawbacks
- Part of the battery's capacity sits idle
- Little or no hydro bill savings
- Longer financial payback
Most systems let you split the difference: reserve part of the battery for backup and cycle the rest. Most homeowners we advise land somewhere in between — for example, keeping 60% charged at all times and using the remaining 40% to pay the hydro bill.
Misconception 3: "My Solar Panels Will Keep My Battery Charged During a Blackout"
They can — in summer. Solar panels can recharge a battery during an outage, but how much energy you get depends on the weather and the time of year.
During summer outages, long days and strong production can refill the battery each day. Critical loads can stay powered for an extended stretch, as long as your panels produce more than your home uses.
Winter outages are harder. Shorter days, weaker production and snow all cut into recharging. If your home is heated with electricity, the battery drains even faster. A solar-and-battery system may not sustain itself through a long winter outage — the time of year you are most likely to need it.
Misconception 4: "The Battery Will Easily Pay for Itself"
Battery payback can easily run past 10 years. It depends on electricity rates, how you use the battery and which incentives apply.
An example: a homeowner installs a 12 kWh battery for $10,000 and uses it for load shifting under Ontario's ULO pricing. If 90% of the capacity is usable and the battery charges overnight and discharges through every weekday peak, it saves about $1,000 a year on electricity. Simple payback: about 10 years.
That is a best-case number. It assumes a low install price, a full cycle every weekday, nothing held back for backup, no charging or discharging losses, rates that stay favourable and enough on-peak use to soak up everything the battery stores. Miss any of those and the payback stretches.
One more variable: Ontario's Home Renovation Savings Program (HRSP) offers battery rebates of up to $5,000 ($300 per kWh). The rebate changes how your system can connect to the grid, so read the trade-off first — see Government Financing and Incentive Programs in Solar Costs & Financing.
Before you buy, check the warranty, expected degradation, round-trip efficiency, and the cost of a replacement. A battery that pays for itself around the time it wears out is not much of an investment.
Misconception 5: "Batteries Are Cheap"
A typical residential battery system costs $10,000 to $20,000 to install, depending on size, electrical upgrades and installation complexity. Whole-home backup or several days of storage may require more than one battery, further increasing the cost.
Battery prices have fallen over time. They are still a major purchase. Decide what you want the battery to do, then ask whether the benefits justify the cost.
Misconception 6: "A Battery Can Be Installed Anywhere"
Not quite. Electrical code, manufacturer requirements, available space and safety rules all limit where a battery can go — it is rarely as simple as hanging it beside the electrical panel.
Garages are usually the best and cheapest location: enough space, and separation from living areas. If the garage lacks the right electrical infrastructure, new wiring, a 240V circuit, or a subpanel can add to the cost.
Outdoor installs are possible, but cold and weather can affect performance and may require a protective enclosure. Mechanical rooms sometimes work, though depending on the layout and local code, they can force renovations.
For some homes, finding a workable spot is the hardest part of the whole installation. Before you spend time comparing batteries, confirm your home has a viable, cost-effective place to put one.
What's Next?
For how batteries work with solar and net meteringA solar system configuration that allows excess solar electricity to be sent to the grid in exchange for hydro bill credits. These credits can then be used to offset future electricity imports. In Ontario, unused credits expire after 12 months., see Batteries and Storage. For rebates and financing options, see Solar Costs & Financing. For what solar does to your hydro bill, see Understanding Your Bill.
Independent Advice on Solar and Battery Storage in Ontario
If you're considering a battery, the Home Solar Accelerator can help.
The Home Solar Accelerator is a free program for homeowners in the Greater Toronto and Hamilton Area that provides independent, expert advice on solar, battery storageA system that stores solar electricity for later use, typically during power outages. Batteries are optional and are not required for net-metered solar systems. and financing. Funded by The Atmospheric Fund, the program helps homeowners understand the trade-offs between backup power, financial savings and system design before making a major investment.
Our independent Solar Advisors can help you:
- Determine whether a battery makes sense for your home
- Compare battery sizes, features and operating modes
- Understand the trade-offs between backup power and financial savings
- Compare solar + battery quotes from vetted local installers
- Review quotes and answer your questions before you commit to an installer
Just getting started? Apply to the Home Solar Accelerator to receive independent advice and multiple quotes from vetted local installers.
Already have a quote? Email it to hello@solaraccelerator.ca for a free independent review.
