Battery Retrofit · Existing Solar Owners
Adding Battery Backup to an Existing Solar Home in Canada (2026)
Last updated November 3, 2026 · Cross-checked against the 2024 Canadian Electrical Code, HRSP + BC Hydro program pages
The short answer
Most Canadian solar owners find this out during their first outage: when the grid goes down, standard solar panels shut off too, even at noon on a sunny day. You don't have to replace your system to fix it. Adding the right equipment — usually a battery plus a switch that cuts your home off from the grid — lets your panels keep working in an outage and stores power for the night. Installed batteries run roughly $700–$1,300 per kWh in Canada.
Not sure if you qualify? We'll check for you.
Battery retrofit rebate rules differ sharply by province — Ontario won't pay for a battery added to existing solar, but BC Hydro will. This guide reflects our best read of HRSP, BC Hydro and the 2024 CEC program pages at time of writing. Rather than track every rule change yourself, request a quote and we'll match you with a vetted Canadian installer who confirms your current eligibility, pins down the exact rebate amount for your home, and handles the paperwork. You're one call away from a real number — free, no obligation.
Key points
- ●Grid-tied solar inverters are required to shut down in an outage so they don't send power into lines that crews are repairing.
- ●To keep using solar in an outage, your home needs a device that isolates it from the grid, plus something that keeps your inverter running — usually a battery.
- ●A battery can be added to almost any existing system without replacing your panels. The most common method is an AC-coupled battery.
- ●Without a battery, only a few setups give you limited daytime power: Enphase IQ8 “Sunlight Backup” and an SMA backup outlet on some inverters.
- ●Installed batteries run roughly $700–$1,300 per kWh in Canada.
- ●Ontario's battery rebate doesn't cover homes that already have solar. BC Hydro does pay for batteries added to existing solar.
Why your solar panels shut off in a power outage
Almost every home solar system in Canada is grid-tied. Its inverter, which turns the panels' DC power into household AC, follows the grid's voltage and frequency. When the grid goes down, the inverter loses that signal and must shut off within seconds.
This is called anti-islanding, and it's required for a good reason. If your inverter kept running, it could send power back into the lines a utility crew believes are dead. See our solar battery backup pillar for the full explanation.
So the fix isn't simply flipping a switch. Your home needs two things:
- A device that disconnects your home from the grid, so your system can't backfeed the lines.
- A power source that keeps your inverter running once you're cut off. In most homes that's a battery, which creates a stable “mini-grid” for your panels to sync to.
The three “switches,” untangled
The word “disconnect” gets used for three different pieces of equipment. Each does a separate job.
| Equipment | What it does | Backup power? |
|---|---|---|
| Backup gateway / automatic transfer switch (Tesla Backup Gateway, Enphase IQ System Controller, FranklinWH aGate) | Senses an outage and disconnects your home from the grid in a fraction of a second, so your battery and solar can run the house safely | Yes — this is the piece that makes backup possible |
| Utility disconnect | A visible, lockable switch your utility requires, so its crews can isolate your system | No — it's a safety requirement |
| Rapid shutdown | Drops the voltage in your rooftop wiring quickly so firefighters can work safely | No — it's a fire-safety requirement |
When you add a battery, your installer will usually install the first and bring the other two up to current code.
Rapid shutdown and the 2024 electrical code
The 2024 Canadian Electrical Code requires rapid shutdown on rooftop solar. Once triggered, wiring more than 1 metre from the array must drop to 30 volts or less within 30 seconds. The switch that triggers it must be easy to reach, usually at the meter on a house, and the system must be labelled.
Ontario's Electrical Safety Authority has required rapid shutdown on new solar installs since May 2016. Older systems may not have it. Adding a battery is a major change that needs a new permit and inspection, so expect your installer to check this and upgrade it if needed.
Where the battery can go
The 2024 code also made home batteries easier to install. Earlier rules sharply limited indoor batteries. The 2024 edition allows up to two 20 kWh batteries inside a home, in a room that meets fire-safety rules, and up to four outdoors or in an attached garage. Each province adopts the code on its own schedule, so your inspector will apply the version in force where you live.
Your upgrade options
Option 1: Add an AC-coupled battery (the usual choice)
This is how most existing systems get backup. The new battery comes with its own inverter and connects on the household (AC) side of your electrical panel, next to your existing solar inverter. Your panels and solar inverter stay as they are.
In an outage, the gateway disconnects your home and the battery takes over. Your existing solar inverter then syncs to the battery as if it were the grid, so the panels keep producing and recharging the battery during the day.
- ●Works with: string inverters and microinverters.
- ●Examples: FranklinWH aPower 2, Enphase IQ Battery 10C, Canadian Solar EP Cube and Tesla Powerwall 3.
- ●Trade-off: slightly lower efficiency, because the power converts from DC to AC and back. Round-trip efficiency is still around 90%.
- ●Switchover: about 20 milliseconds on good systems, fast enough that most electronics won't notice.
Option 2: Replace the inverter with a hybrid (DC-coupled)
Here your old solar inverter is swapped for a hybrid inverter that handles both the panels and the battery. It's more efficient, but it means more new equipment, re-permitting the solar side and some downtime. It makes most sense when your existing inverter is near the end of its life anyway.
Already have a hybrid inverter? Some systems were installed “battery-ready.” Adding storage can then be fairly simple. Check your inverter's list of compatible batteries first.
Option 3: Daytime solar power without a battery
If you mainly want your panels to keep a few things running during a daytime outage, a couple of setups can do that without a battery. Both have real limits.
Enphase IQ8 “Sunlight Backup”
IQ8 microinverters can form their own mini-grid. With the right Enphase control equipment, they can power a small set of essential, low-draw loads during daytime outages only. A load controller sheds everything else to keep the system stable. If you have older Enphase IQ7 microinverters, this would mean replacing them.
SMA Secure Power Supply
Some SMA Sunny Boy string inverters have a dedicated backup outlet that delivers roughly 1,500–2,000 watts while the sun is shining. It's one outlet, switched on manually, and not suited to anything with a big startup surge. If your SMA inverter has this feature, it may only need an outlet installed.
Why a battery is still the better fix: without one, power drops every time a cloud passes, and it stops entirely at sunset. You also can't run a furnace fan or a well pump reliably.
Option 4: No solar yet? Start with the switch
You can add a battery without any panels, and in BC it can even earn a rebate (see below). The catch is that the battery can't recharge during a long outage. Some homeowners do it in stages: the gateway and a backed-up circuit panel first, then the battery, then panels later.
A word on generators
If you already have a generator, it needs its own approved transfer switch or interlock. Never backfeed a house through a dryer outlet or a “suicide cord.” It can electrocute utility workers and anyone touching the other end of the cord. If you want a generator and a battery together, tell your installer up front, because not every battery system is designed to work with one. Our solar + battery backup pillar compares the two.
Not sure if your inverter can take a battery?
Share your inverter make + model with a vetted local installer and they'll tell you whether an AC-coupled retrofit works, whether a hybrid replacement is cheaper, and whether your system needs a rapid-shutdown upgrade too. Free, no obligation.
What a retrofit looks like
A typical Canadian AC-coupled retrofit goes like this:
- Assessment. The installer checks your inverter model, its output and your electrical panel's capacity.
- Design and permits. Engineering, an updated wiring diagram showing the disconnect locations, a municipal or provincial electrical permit, and your utility's connection approval.
- Install. About one day on site for most homes.
- Inspection and commissioning. From signing to a working battery usually takes 4–6 weeks.
A battery-only retrofit typically doesn't need a new meter.
What it costs in Canada
Installed home batteries run roughly $700–$1,300 per kWh of usable storage:
| Usable capacity | Low ($700/kWh) | Mid ($1,000/kWh) | High ($1,300/kWh) |
|---|---|---|---|
| 5 kWh | $3,500 | $5,000 | $6,500 |
| 10 kWh | $7,000 | $10,000 | $13,000 |
| 13.5 kWh | $9,450 | $13,500 | $17,550 |
| 15 kWh | $10,500 | $15,000 | $19,500 |
| 20 kWh | $14,000 | $20,000 | $26,000 |
Some real installed package prices before rebates and tax:
- ●16 kWh Renon system: $20,699
- ●One Tesla Powerwall 3 (13.5 kWh): $23,997
- ●Two Powerwalls (27 kWh): $37,346
Older homes may need extra electrical work. If your main panel is too small for the gateway or a backed-up circuit panel, a panel replacement can add around $2,200. Ask every installer to include this in the quote, along with permits and inspection.
How big a battery do you need?
- ●Essentials only: fridge, lights, Wi-Fi, phone charging and the furnace fan typically draw 700–900 watts. A 10–15 kWh battery covers that comfortably.
- ●Whole home: generally 20 kWh or more.
- ●Electric heat: baseboards or a heat pump without a backup will drain a home battery quickly. Plan to keep those off the backed-up circuits.
Plan for a winter outage. Ice storms usually happen when solar output is at its lowest, and snow can cover the panels. In December, expect your panels to recharge the battery only a little each day, so size the battery for the loads you'll need without much help from the sun.
Rebates for existing solar homes
Rebate rules are where retrofit projects most often go wrong.
| Province | Battery added to existing solar | Battery with no solar |
|---|---|---|
| Ontario HRSP | Not eligible — must have no existing solar or battery system | Not eligible — must be installed with new rooftop solar |
| British Columbia BC Hydro | Eligible — up to $1,500, or up to $5,000 if enrolled in Peak Saver | Only if enrolled in Peak Saver — up to $5,000 |
| Federal | No home battery rebate in 2026 — see what replaced the Greener Homes Grant | |
Ontario
The battery rebate is only for first-time solar and battery installations, and expanding an existing system doesn't qualify. If you already have panels, plan your retrofit without it. See our Ontario solar rebate guide.
British Columbia
BC Hydro says a battery can be added to an existing solar system or installed with no solar at all. To qualify:
- ●Get pre-approval before you buy.
- ●Use a Home Performance Contractor Network installer.
- ●Choose a battery from BC Hydro's qualified list (Tesla isn't eligible).
- ●For the $5,000 amount, enroll the battery in Peak Saver within 14 days of interconnection approval.
Customers who take only a battery rebate keep their current rate, so an existing net metering customer stays on net metering. See our BC Hydro rebate guide.
Your upgrade checklist
checklistBattery Retrofit Checklist
- Find your inverter's make and model. It's on the label of the box near your panel or on your original paperwork. This decides which batteries will work and whether you have a no-battery option.
- Decide what you want to keep running. Essentials only, or the whole house? Make a list: fridge, furnace fan, sump pump, well pump, medical equipment.
- Check your rebate BEFORE you buy. In BC, get pre-approval first. In Ontario, assume no rebate if you already have solar.
- Get at least two quotes that include the battery, gateway, any panel upgrade, rapid-shutdown work, permits and inspection.
- Ask each installer: Does my current inverter work with this battery, or does it need replacing? Will my panels keep charging the battery during an outage? Does my system need a rapid-shutdown upgrade? Which circuits will be backed up? How long will the battery run essentials with no sun?
Get a detailed retrofit quote
Every home's inverter, panel and power needs are different. Required contact info ships straight to a vetted local installer who will confirm your current inverter will work with their battery and that your panels will keep charging it in an outage.
Related reading
Solar battery backup — 3 to 7 day outage pillar
Deep dive on the full backup story: generator comparison, winter solar yield, and how to size for Canadian climate.
Tesla Powerwall Canada 2026 — Cost + Rebate + Alternatives
Powerwall is a strong AC-coupled retrofit pick in Ontario; alternatives are the better call in BC since Tesla is excluded there.
BC Hydro solar + battery rebate 2026
The full BC retrofit rebate story — Peak Saver, HPCN contractor rule, and which batteries qualify.
Ontario HRSP solar + battery rebate
Why retrofits don't qualify in Ontario and what the net-metering tradeoff looks like for new installs.
Frequently asked questions
Do solar panels work during a power outage?
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Can I add a battery to my existing solar system?
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Can I use my solar panels in an outage without a battery?
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Is a transfer switch enough to run my house on solar?
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Do I need to upgrade my disconnect switch to add a battery?
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How much does it cost to add a battery to existing solar in Canada?
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Does a battery added to existing solar qualify for Ontario's rebate?
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Does BC Hydro give a rebate for adding a battery to existing solar?
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How long will a home battery last in an outage?
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Get retrofit quotes for your home
Every home's inverter, panel and power needs are different. We match you with vetted Canadian installers who confirm your inverter model will work with their battery and that your panels will keep charging it in an outage.
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Last updated November 3, 2026. Electrical code adoption and rebate rules vary by province and change often. This guide is compiled to the best of our ability from the 2024 Canadian Electrical Code and official program pages at time of writing. Confirm requirements with your installer, your local inspection authority and your utility before you buy.