Quick answer
A home battery has two separate limits:
kW determines what you can run. kWh determines approximately how long you can run it.
A large battery can still fail to start a pump, compressor, heat pump or other load if its inverter output, motor-start capability, voltage or electrical integration is wrong. The reverse is also true: a powerful inverter can run a large load but drain a modest battery quickly.
For outage planning, check at least five things:
- Continuous power: what must be able to run at the same time.
- Starting / inrush power: what motors and compressors require to start.
- Stored energy: how many kWh your loads consume over the outage window.
- Voltage and connection: especially 240 V and hardwired equipment.
- Integration: standalone appliance backup, selected circuits, or whole-home electrical backup.
Use the Home Battery Backup Calculator to size power and energy separately from the loads you actually care about.
What counts as a home battery?
The market has blurred the old line between “portable power station” and “installed battery.” A more useful way to compare systems is by integration level.
Swipe across the table to compare all columns.
| Integration level | What it usually means | Best fit |
|---|---|---|
| Standalone appliance backup | Battery station powers devices directly from its outlets | Fridge, networking, lights, electronics, selected plug-in loads |
| Modular home backup | Large expandable battery system can work standalone or with manufacturer-approved home equipment | Larger outage loads with a path toward circuit integration |
| Essential-load integrated battery | Permanently connected system backs selected circuits through approved transfer/islanding equipment | Refrigeration, furnace, sump, well, communications and other priorities |
| Whole-home integrated battery | Gateway/controller can energize most or all of the home’s distribution system while isolated from the grid | Broader automatic backup, usually with active load management |
A product such as a large EcoFlow or Anker system may sit in more than one row depending on how it is configured. The brand name does not settle the category. The electrical connection does.
For ordinary portable shopping, use the portable power station guide. This page owns the installed and home-integrated battery decision.
kW: can the battery run the load?
Continuous output is the inverter power a system can sustain. Start there before looking at battery capacity.
If your must-run loads total 4 kW at the same moment, a battery system with 3 kW of available backup output does not become adequate because it has 20 kWh of storage.
Motor and compressor starts are a separate check
Pumps, older compressors and some blowers can need substantially more current while starting than while running. But there is no defensible universal rule such as “multiply every motor by 3.”
Use, in order of preference:
- measured inrush/start data for the exact equipment,
- manufacturer locked-rotor or starting-current data,
- equipment-specific documentation,
- a conservative placeholder only when it is clearly labelled as uncertain.
The well-pump outage guide, sump-pump battery backup guide, and furnace outage guide own the deeper equipment-specific checks.
120 V versus 240 V still matters
Canadian houses commonly have 120 V branch circuits plus 240 V loads. A battery with enough headline kW and kWh can still be incompatible with a load if the backup architecture cannot supply the required voltage and phase arrangement.
Common 240 V candidates include some well pumps, heat pumps, central air conditioners, electric water heaters, ranges, dryers, EV chargers, and electric resistance heating. Do not infer 240 V capability from battery capacity or a large inverter number.
kWh: how long can the battery run it?
Stored energy is the runtime side of the problem.
A simple load-side planning equation is:
Required delivered energy (kWh) = average backed-up load (kW) × outage duration (hours)
But “average backed-up load” is not the same as adding every appliance nameplate and assuming everything runs continuously. Separate loads into continuous, duty-cycled, intermittent, motor/compressor, and optional/deferrable loads. The calculator asks for those operating patterns instead of hiding generic duty-cycle assumptions.
Nameplate kWh is not guaranteed delivered AC energy
A battery’s advertised energy capacity is not automatically the number of kWh that reaches household loads. Depending on the system, the result can be affected by usable-capacity limits, state-of-charge reserve settings, conversion losses, inverter and gateway self-consumption, thermal management, load level, temperature, and battery condition.
ReadyHome therefore does not use one universal efficiency factor or one universal “leave 20% in reserve” rule. When a purchase decision depends on it, use the exact system’s current technical documentation or measured delivered-energy data.
Essential-load backup vs whole-home backup
This is usually a better first decision than choosing a battery brand.
Essential-load backup
You deliberately protect the circuits that matter most, potentially including refrigeration, Wi-Fi and communications, selected lighting/receptacles, a fuel-burning furnace’s controls/blower, sump pump, well pump, and other critical equipment. The exact list depends on voltage, startup demand, wiring and the system design.
Whole-home backup
“Whole-home” often describes how broadly the battery is connected to the home’s electrical distribution. It does not mean every electric load can operate at full power at the same time.
A home may have access to the entire panel during an outage while still needing to shed, throttle or defer EV charging, electric water heating, range/oven loads, clothes drying, central air conditioning, auxiliary resistance heat, or other high-demand circuits.
That is why load management can be more valuable than simply buying more battery.
Load management can shrink the power requirement
A smart panel, load-control module, contactor, gateway, or homeowner operating plan can keep large loads from stacking together. Without management, the design must accommodate more simultaneous demand. With manual or automatic management, essential loads can stay available while discretionary loads are rotated or shed.
Ask an installer which loads are actually controllable, what happens if communications fail, and whether the load-control hardware still behaves safely during an outage.
Do you need solar for a home battery?
No. A compatible home battery can charge from the utility grid and provide outage backup without rooftop solar. Some systems can also use time-of-use charging/discharging when the utility tariff and product configuration make that useful.
Without solar, outage energy is finite until the grid returns or another supported recharge source is available.
Solar during an outage is not automatic
Ordinary grid-tied solar is designed to stop exporting into a dead utility grid. For solar to continue serving the home during an outage, the overall system needs approved islanding/backup equipment and compatible controls that safely isolate the premises and form the local electrical system.
Even then, solar recharge depends on system architecture plus season, cloud cover, snow, shade, array size/orientation, battery state of charge, household load, and PV/inverter compatibility while islanded.
Canadian context
Do not subtract a made-up “Canadian winter solar percentage” from the battery you need. Natural Resources Canada’s PV maps are location- and month-specific and explicitly note that real output varies and snowfall is not fully captured. For resilience planning, size first-charge battery runtime without guaranteed solar, then model solar as a separate recharge scenario.
Can a generator and home battery work together?
Sometimes, and the combination can be excellent for long outages. A supported hybrid design can let the battery handle quiet low-load periods while a generator supplies loads and/or replenishes storage when needed.
Potential advantages include fewer generator run hours, quiet overnight backup, less dependence on one energy source, battery support between generator runs, and solar recharge when conditions allow.
But generator integration is product-specific. Do not assume any portable or standby generator can be connected to any battery or gateway simply because the voltage looks right.
Use the portable generator guide and generator transfer-switch guide for generator-specific hardware and safety.
Home battery vs generator
Neither wins every Canadian outage.
Swipe across the table to compare all columns.
| Decision factor | Home battery | Generator |
|---|---|---|
| Automatic response | Common with integrated systems | Common with standby units; portable units are usually manual |
| Noise / exhaust | No combustion exhaust during normal battery operation | Combustion noise and exhaust; generator safety rules apply |
| Stored-energy limit | Finite until recharged | Can continue while a safe fuel supply remains available |
| Frequent short outages | Strong fit | Often more machine than the outage needs |
| Long winter outages | Requires enough storage or a recharge plan | Often strong where fuel can be stored/supplied safely |
| Large sustained loads | Can require load management or multiple units | Larger generators may support high sustained loads more economically |
| Solar integration | Can extend endurance in a compatible islanded system | Does not require solar |
| Mechanical maintenance | No engine maintenance | Engine, fuel and maintenance requirements apply |
| Electrical installation | Integrated systems require professional design and permits | Household-circuit generator connections also require approved transfer equipment and electrical work |
For some rural or high-resilience homes, the best answer is battery + generator, not battery versus generator.
Home battery vs portable power station
Use this shortcut:
- If you mainly want to plug a few appliances directly into a battery, start with a portable power station.
- If you want automatic backup of selected household circuits, start thinking about an integrated residential battery system.
- If you want most or all of the panel available during an outage, you are firmly in gateway/load-management/electrical-design territory.
Some large modular systems can move between those levels with manufacturer-approved panels or transfer equipment. That is why integration level is more useful than arguing about whether the product has wheels.
Heat pumps, water heating, cooking and EV charging
These loads are where casual “one battery runs the house” claims fall apart.
Heat pumps
A heat pump’s exact compressor, controls, voltage, low-temperature behaviour and auxiliary resistance heat matter. Auxiliary strip heat can be a very large sustained load, but its rating is equipment-specific. Never size from the phrase “3-ton heat pump” alone.
Electric water heating
Tank, heat-pump and tankless electric water heaters can have dramatically different power profiles. A tankless unit may present an especially large instantaneous load even if the household’s total daily hot-water energy is modest.
Cooking
Ranges and ovens can be high-power loads, while kettles and microwaves are high-power but usually brief. Runtime math should reflect duration, not just nameplate watts.
EV charging
Level 2 EV charging can consume a large share of residential battery output and stored energy. That does not make EV charging “wrong” during an outage, but it should be an explicit priority decision and is often an obvious candidate for load shedding.
Vehicle-to-load (V2L), vehicle-to-home (V2H), and vehicle-to-grid (V2G) are different technologies. A vehicle with an AC outlet is not automatically a whole-home V2H system.
Cold weather: use the exact system limits
Do not use a blanket rule such as “lithium batteries cannot charge below 0°C.” Some systems include active heating or thermal management that changes their allowable charging behaviour.
For every Canadian installation, verify the exact model’s charging, discharge and storage temperature ranges; self-heating/thermal management; output derating; indoor/outdoor rating; enclosure rating; and mounting/clearance requirements. A system that can discharge at -20°C may not accept charging the same way at -20°C. The manual wins.
Installation, certification and permits in Canada
A permanently connected residential energy-storage system is electrical infrastructure, not a weekend panel project.
There is no one Canada-wide “40 kWh per house” rule
This is an area where oversimplified summaries get dangerous.
Ontario’s current Electrical Safety Authority residential ESS bulletin, for example, distinguishes locations. It allows up to 20 kWh for a single ESS, while aggregate limits can differ by installation location: the bulletin describes up to 80 kWh at attached garages/exterior surfaces and 40 kWh in qualifying dedicated/utility rooms.
That alone is enough to reject a blanket statement such as “Canada limits every dwelling to 40 kWh.”
Provincial code adoption also changes over time. British Columbia’s 2024 Electrical Code took effect March 4, 2025, while Alberta put CSA C22.1-24 in force April 1, 2025. Verify the current provincial and local rules for the actual permit date and installation.
Basement installation is not a yes/no national rule
Do not assume batteries are either universally allowed or universally banned in Canadian basements. Location rules can depend on adopted code edition, province and local authority, system certification, unit/aggregate capacity, room construction, fire separation, exits/dwelling configuration, and manufacturer limits.
If your proposed location is below grade, in a garage, near an exit, exposed to vehicles, or vulnerable to flooding, put that question near the top of the contractor/design conversation.
UL 9540 and UL 9540A are not the same thing
UL Solutions describes UL 9540 as a standard for energy storage systems and equipment. UL 9540A is a test method used to evaluate thermal-runaway fire propagation behaviour.
So “UL 9540A certified” is not a useful consumer shortcut by itself. Ask for the exact Canadian product approval/listing evidence required by your jurisdiction and utility, and confirm that the complete installed combination is approved for its intended use.
Flood and water exposure
A residential battery can contain hazardous energy even when the utility is down. If a battery, gateway or related electrical equipment is submerged, wet or visibly damaged after flooding:
- do not approach or touch it while water/electrical hazards remain,
- do not operate its switches or try to restart it,
- keep people away from the area,
- contact the utility/emergency services when isolation is required,
- have the system assessed under the manufacturer and local electrical-safety process before re-energization.
Do not assume “drying it out” makes high-energy electrical equipment safe.
Current Canadian home-battery rebates: September 2026
Programs change quickly. Treat this as a dated snapshot, not a permanent promise.
Swipe across the table to compare all columns.
| Jurisdiction | Current status | Key battery detail |
|---|---|---|
| Federal Canada Greener Homes Grant / Loan | Closed to new participation | The grant is closed and the loan funding is fully committed; do not market these as current battery financing |
| BC Hydro | Active, eligibility-specific | $500/kWh; residential maximum $1,500 when installed with solar, or up to $5,000 for eligible batteries enrolled in Peak Saver; battery-only systems not enrolled in Peak Saver are not eligible |
| Ontario Home Renovation Savings | Active, solar-paired | Battery storage $300/kWh up to $5,000 and 50% of eligible costs; the battery must be paired with a new solar PV system; solar can receive a separate rebate up to $5,000 |
Two important catches:
- BC Hydro requires pre-approval and specific product/installation eligibility. Its current program terms also exclude Tesla battery models from new rebate eligibility except specified grandfathered circumstances.
- British Columbia’s PST Bulletin 203 says batteries are generic goods and do not qualify for the clean-energy equipment PST exemption simply because they are used with solar/wind/micro-hydro equipment.
Always re-check the administering authority before signing a contract around an incentive.
What do home batteries cost in Canada?
There is not enough authoritative national evidence to publish one honest “average installed battery cost” as if Vancouver, Edmonton, Toronto and a rural acreage were the same job.
Ask for a quote that breaks out battery modules, inverter/power conversion, gateway/transfer equipment, essential-load subpanel or load-control hardware, service upgrades, electrical labour, permits/inspection, utility interconnection, mounting/structural work, solar integration, generator integration, and taxes.
That breakdown is more useful than a national range built from a few installer sales pages.
Current system examples in Canada
These are examples of architectures, not ReadyHome rankings. Specifications and availability can change, so verify current Canadian documentation before buying.
Swipe across the table to compare all columns.
| System | Current published energy / power example | Why it is useful in the comparison |
|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh; 11.5 kW continuous backup; 185 LRA motor-start rating | High-output integrated residential battery; useful example of why kWh and motor capability are separate specs |
| Enphase IQ Battery 5P | 5.0 kWh usable; 3.84 kW continuous per unit; modular | Shows how multiple smaller battery/inverter units can build a larger system |
| FranklinWH aPower 2 | 15 kWh; 10 kW discharge; 185 LRA published motor capability | Whole-home architecture paired with aGate and load/generator integration options |
| Generac PWRcell 2 | 9-18 kWh usable per cabinet; output changes with module count, up to 11.5 kW with supported configurations | Strong example of why one product name can represent several energy/power configurations |
| EcoFlow DELTA Pro Ultra + Smart Home Panel 2 | About 6 kWh / 7.2 kW per inverter-battery starting configuration, expandable with home-panel integration | Demonstrates the blur between large modular power stations and installed home backup |
| Anker SOLIX F3800 / F3800 Plus family | 3.84 kWh / 6 kW starting unit class with 120/240 V home-integration options | Another modular system that can move from appliance backup toward household-circuit integration |
Do not rank these by kWh alone. Compare usable energy, continuous output, starting capability, voltage, load management, expansion, cold-weather limits, certification, warranty, generator/solar integration and installer support.
A better installer conversation
Instead of asking “How many Powerwalls do I need?”, bring these questions:
- What are my must-run loads, and what are their actual voltages and startup requirements?
- What continuous kW can the system deliver while islanded?
- Which loads will be shed or deferred during an outage?
- What usable AC energy should I expect from the proposed configuration?
- Which settings reserve energy for outages versus daily use?
- Can solar recharge the battery while the grid is down in this exact design?
- Can a generator be integrated later, and only through which approved equipment?
- What happens at the coldest temperature expected at the installation location?
- Is the proposed battery location compliant with current provincial/local rules?
- Which permits, utility approvals and inspections are included in the quote?
- What exactly does the warranty guarantee, and what cycling/throughput limits apply?
- What changes if I add a heat pump, EV charger or second battery later?
Frequently asked questions
How much home battery backup do I need?
You need two answers: enough kW to run and start the loads that can overlap, and enough kWh to supply their average energy use for your target outage duration. Use the home battery backup calculator with your actual equipment data.
How long will a 10 kWh or 13.5 kWh home battery last?
There is no fixed answer. Runtime depends on usable delivered energy and average load. A 500 W average outage load and a 5 kW average outage load produce radically different runtime from the same battery.
Can I have home battery backup without solar?
Yes, if the system is designed to charge from the grid and provide backup. Without solar or another supported recharge source, the outage duration is limited by the stored energy available when the grid fails.
Does whole-home battery backup mean I can run everything normally?
No. Whole-home can describe the electrical integration. The inverter still has a power limit, and load management may be required to keep high-demand circuits from operating together.
Can a home battery run my heat pump?
Potentially, but only after checking the exact heat pump, compressor/start behaviour, 240 V requirements, auxiliary resistance heat and the battery system’s islanded output. Do not size from tonnage alone.
Can I install a home battery in my basement?
Possibly in some jurisdictions/configurations, but there is no safe Canada-wide yes/no answer. Location rules depend on code adoption, capacity, room construction, exits, certification, manufacturer instructions and the local authority having jurisdiction.
Is a battery better than a generator?
For quiet automatic backup and frequent shorter outages, a battery can be excellent. For very long outages or high sustained loads, fuel generation can be more practical. A hybrid can be stronger than either alone when the system is deliberately designed for it.
Methodology and primary sources
Methodology
This guide was built from September 2026 Canadian keyword research, a long-form residential energy-storage research dossier, and an independent source-by-source reconciliation before implementation. The dossier was treated as a hypothesis set rather than publication-ready truth. We rejected its blanket Canada-wide 40 kWh limit, universal basement prohibition, BC battery PST-exemption claim, fixed motor multipliers, fixed inverter/tare assumptions, fixed winter-solar cap, stale incentive details, and several mixed-generation product specifications.
Primary sources checked include Natural Resources Canada resiliency guidance, the current Canada Greener Homes Loan status, BC Hydro solar/battery rebate terms and connection requirements, the Ontario Home Renovation Savings solar/storage program, the Ontario Electrical Safety Authority ESS bulletin, the BC Electrical Code adoption page, Alberta’s electrical-code page, and UL’s ESS standards overview plus its UL 9540A test-method explanation.
Current manufacturer examples were checked against first-party Tesla, Enphase, FranklinWH, Generac, EcoFlow and Anker documentation. Brand specifications, prices, rebates, certifications and availability can change; this page uses them to illustrate architecture, not to declare a permanent “best battery.”