Ontario's current electrical code gives a home battery four approved homes: the exterior wall of the house, an attached garage, a detached garage or other free standing structure, or a dedicated room or utility room built to fire construction minimums. Bedrooms are prohibited, and the capacity cap changes with the location.
Where you can install a home battery in Ontario also decides how large it can be and part of the installation cost. The rules come from the current Ontario Electrical Safety Code, the 2024 edition, which the Electrical Safety Authority confirms took effect on May 1, 2025 and which remains in force as of September 2026, along with ESA Bulletin 64-8-3, which explains how Rule 64-1100 applies at homes. This guide covers each location, the limits, and what to confirm before you sign.
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In this guide
- Which four locations does Ontario's code approve?
- How much battery capacity does each location allow?
- Can you install a home battery in the basement in Ontario?
- What clearance and room rules apply?
- How does location change your quote and the HRS rebate?
- What should your battery quote confirm in writing?
Which Four Locations Does Ontario's Code Approve?
Rule 64-1100 of the current code lists where an energy storage system may be installed at a home. One option is the exterior surface of the building, a wall mounted unit outside the house. Outdoor rated units are built for this, but cold weather performance varies by product.
A second is an attached garage, which keeps the battery out of living space and often close to the electrical panel. A third is in or on an associated detached garage or other free standing structure on the property.
The fourth is a dedicated room or utility room inside the home. According to ESA Bulletin 64-8-3, that room needs a door with a self closing device, gypsum board walls and ceilings with joints sealed, and a lumber sheathed floor. Materials with higher fire resistance also qualify, so a concrete basement floor counts.
One location is banned outright: sleeping areas and rooms that open directly into them.
How Much Battery Capacity Does Each Location Allow?
A kilowatt hour (kWh) measures stored energy, and both battery sizes and the code's capacity limits are stated in kWh. The current code raised the outdoor and attached garage limits.
| Location | Capacity limit | Key conditions |
|---|---|---|
| Exterior wall of the home | Up to 80 kWh (raised from the previous 40 kWh limit) | At least 1 m from windows and doors; follow the manufacturer's outdoor rating |
| Attached garage | Up to 80 kWh (raised from the previous 40 kWh limit) | At least 1 m from windows and doors, other than a vehicular access door |
| Dedicated room or utility room | 20 kWh per single system, 40 kWh aggregate for multiple systems | Self closing door, gypsum board walls and ceiling, lumber sheathed floor or better |
| Detached garage or free standing structure | Permitted location; confirm the capacity treatment for this location with your contractor and ESA | Spacing between systems still applies |
Source: ESA Bulletin 64-8-3 and the Ontario Electrical Safety Code (2024 edition, in force since May 1, 2025), Rule 64-1100. Figures verified current as of September 2026.
Three bulletin details matter for real quotes. The limits apply to the battery portion only, not the inverter or other connected equipment. Battery groupings cannot exceed 20 kWh and must sit at least 1 m apart or as the manufacturer's instructions direct. ESA also permits a 5 percent tolerance on total aggregate capacity, which is why a 20.2 kWh nameplate can still pass indoors. Our guide to the best solar batteries in Canada shows how common unit sizes line up against these caps.
Can You Install a Home Battery in the Basement in Ontario?
Yes, with conditions. The bulletin confirms that a battery may be installed below the lowest level of egress, which covers most basements, as long as the dedicated room or utility room requirements are met: the self closing door, gypsum board walls and ceiling, and a compliant floor. The 20 kWh per system and 40 kWh aggregate limits apply there too.
Every indoor installation adds one requirement: a smoke alarm or smoke detector in the room that holds the battery, interconnected where the Ontario Building Code requires it.
Open living space is different. The code allows batteries in habitable areas only when the product carries cell level fire test markings under the UL 9540A standard, and as of the bulletin's May 2025 issue date ESA was not aware of any approved products in Canada bearing them. A living room battery is not a realistic option today.
What Clearance and Room Rules Apply?
Batteries that form part of an energy storage system cannot sit within 1 metre of any window or door of the home, indoors or outdoors. The one exception is a vehicular access door, which keeps garage installs workable.
With more than one system, the batteries must sit at least 1 metre apart. ESA accepts less only when the manufacturer's instructions specify it and the product is certified to the second or third edition of the UL 9540 standard, with the certification and instructions provided as proof.
Rooms also need working space. The bulletin sets the minimum room size at the equipment depth plus 1 metre of clear space in front, with at least 2 metres of height.
Two situations carry extra rules. In a building with multiple dwelling units, the dedicated room needs a fire resistance rating of at least 1 hour, verified with the local authority, and batteries cannot sit directly beneath a required exit. On rural or multi building properties, a structure built solely to house battery equipment falls outside the residential rule but must keep at least 3 metres of clearance from the home.
See what a battery could save on your Ontario hydro bill
How Does Location Change Your Quote and the HRS Rebate?
Location moves installed cost through labour and materials rather than the battery price. Longer wiring runs to a detached structure, trenching, wall reinforcement, or building a compliant dedicated room all add work. A spot near the panel that already meets the clearance rules is usually the least expensive path, but the site visit decides what your house allows.
Location also interacts with capacity, and capacity drives the rebate. As of September 2026, the Home Renovation Savings program pays $300 per kWh of battery storage, up to $5,000 and no more than 50 percent of total costs. At the published rate, a 13.5 kWh unit works out to $4,050, and the cap is reached at about 16.7 kWh. Both fit inside the 20 kWh indoor limit, so the room rules rarely block the rebate, though they can block a second battery indoors.
The program's conditions are strict. The battery must be paired with a new solar system, sized to it, and designed to primarily store solar energy. Load displacement means all the electricity your system generates is used on site instead of being exported to the grid, and program participants are not eligible for a net metering agreement with their utility. Written pre approval is required before any equipment is purchased or installed. Our comparison of the HRS rebate and net metering paths in Ontario walks through that choice, and rebate amounts are estimates until the program approves your application.
One honest limit: an online estimate models savings by rate plan and system size, but only a site visit can confirm which of the four locations works at your house and what it costs to build there.
What Should Your Battery Quote Confirm in Writing?
Before you sign, the quote or contract should state:
- The proposed location and how it complies with Rule 64-1100 of the current code.
- The total battery capacity and the limit that applies to that location.
- The clearance distances from windows, doors, and any second system.
- The smoke alarm plan for any indoor installation.
- Who files the ESA notification and who obtains connection authorization from your utility. A battery is electrical work for a licensed electrical contractor.
- For rebate projects, confirmation that written pre approval will be in place before any equipment is ordered.
An installer who puts these in writing is planning around the code rather than habit. It is the kind of paperwork we look for when screening companies, described on our installer vetting criteria page.
Deciding Where to Install a Home Battery in Ontario
Where you can install a home battery in Ontario comes down to four code approved locations, each with a capacity ceiling: up to 80 kWh in an attached garage or on an exterior wall, and 20 kWh per system in a compliant dedicated or utility room. The right spot balances those limits against wiring distance, winter exposure, and what you want the battery to do. Our overview of solar in Ontario covers how batteries fit the bigger provincial picture.
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Frequently Asked Questions
Common questions readers ask about this topic
No. Rule 64-1100 of the Ontario Electrical Safety Code prohibits energy storage systems in sleeping areas and in rooms that open directly into sleeping areas. If a battery is installed anywhere inside a dwelling, a smoke alarm or smoke detector must also be installed in the room that holds it.
The code permits batteries on the exterior wall of a home, and outdoor installations carry the higher 80 kWh capacity limit. Cold performance depends on the product, not the code. The battery must be installed following the manufacturer's instructions, so check the published operating temperature range for the exact model in your quote before agreeing to an outdoor location.
A dedicated room or utility room can hold up to 20 kWh for a single energy storage system, or 40 kWh in aggregate where multiple systems are installed. ESA permits a tolerance of up to 5 percent on total aggregate capacity. The limits apply to the battery portion only, not to inverters or other connected equipment.
Yes. A home battery is electrical work under the Ontario Electrical Safety Code, so the installation must be filed with the Electrical Safety Authority and completed by a licensed electrical contractor. Grid connected systems also need connection authorization involving your local utility. Ask your installer to confirm in writing who files the notification and who manages the utility approval.
The rebate rules do not name locations, but the system must meet ESA requirements, and as of September 2026 the battery must be paired with a new solar system, sized to it, and designed for load displacement only. The rebate pays $300 per kWh up to $5,000 and no more than 50 percent of costs, with written pre approval required before purchase or installation.
Batteries that form part of an energy storage system cannot be located within 1 metre of any window or door of the home, whether installed indoors or outdoors. A vehicular access door, such as the main garage door, is the one exception. Where multiple systems are installed, the batteries must also sit at least 1 metre apart unless the manufacturer's certified instructions permit less.
Editorial note: Placement, capacity, and clearance rules on this page come from the current Ontario Electrical Safety Code (2024 edition, in force since May 1, 2025) and ESA Bulletin 64-8-3, verified in force as of September 2026. Rebate figures come from the Home Renovation Savings program, and program terms can change on the administrator's own schedule. Confirm current code and program status with the Electrical Safety Authority, your Licensed Electrical Contractor, and the rebate administrator before making a purchase decision.
Sources
- Electrical Safety Authority, ESA Bulletin 64-8-3, Battery based energy storage systems (ESS) at residential occupancies.
- Electrical Safety Authority, Ontario Electrical Safety Code (2024 edition, effective May 1, 2025).
- Save on Energy and Enbridge Gas, Home Renovation Savings program, solar panels and battery storage rebates.