What a home battery actually does
A home battery stores electricity to use later. In Alberta, most people consider one for two reasons: backup power during outages, and storing daytime solar for use in the evening instead of exporting it.
The first reason is usually the stronger one. Under Alberta's net billing rules, exported solar earns a credit at your energy rate, so the financial gain from storing it yourself depends a lot on your retail plan. For many households, the battery's main value is keeping the furnace, fridge and sump pump running when the power goes out in January.
It is worth being clear about what a standard solar system does without a battery: it shuts down during an outage. That surprises a lot of people. If backup matters to you, the battery (or another backup source) is what provides it.
How backup power is wired
A battery system for backup has three main parts: the battery and its inverter, a device that disconnects your home from the grid during an outage (often called a gateway or transfer device), and a way to choose which circuits stay on.
Most homes back up a critical loads panel: a smaller subpanel with the circuits you cannot do without. Large loads like the range, dryer, hot tub and EV charger stay on the main panel and go dark in an outage. Larger systems can back up the whole house, but that takes more battery capacity and careful load planning.
The isolation step is not optional. A battery must never send power back into utility lines during an outage, where it could injure line crews. Certified equipment and a proper installation make sure it cannot.
What an outage looks like with a battery
How long the battery lasts depends on its size and what you run. A furnace blower, fridge and a few lights can run for a long time. Adding electric heat, a kettle and a hair dryer drains it quickly. In a multi-day winter outage with little sun, even a large battery will eventually run down.
Choosing what to back up
Picking the circuits for a critical loads panel is the most important design conversation. Walk through your home and think about a two-day outage in February. Most Edmonton households end up with something like this:
- Furnace (the blower and controls, even with a gas furnace, which cannot run without power).
- Fridge and freezer.
- Sump pump, especially in neighbourhoods with high water tables.
- A few lighting circuits in the kitchen, bathroom and main living area.
- Internet, phone charging and a couple of outlets for a laptop or medical device.
- Well pump on an acreage.
Leave out anything with a heating element where you can: baseboard heaters, the range, the dryer, the hot tub and the EV charger. Those are the loads that empty a battery in hours instead of days. A designer will check the starting current of motors like well pumps too, since the inverter has to handle that surge.
If you work from home or someone in the household relies on powered medical equipment, say so early. It changes what goes on the list and how much capacity is worth paying for.
Where a battery can go in an Edmonton home
Location is governed by the electrical and fire codes and by the manufacturer's instructions, and the rules for where lithium batteries may go in a dwelling have been getting more specific. Garages, utility rooms and exterior walls are common locations. Some rooms are not permitted at all.
Cold matters too. Many lithium batteries cannot charge below freezing unless they have built-in heating, and their capacity drops in the cold. An unheated Edmonton garage at -30 C is a very different environment from a mild climate. Check the battery's temperature ratings, and expect your installer to ask about this.
Battery systems store a lot of energy and can deliver very high fault currents. Installation, connection to your panel and any service work must be done by a licensed electrician under a permit.
Battery or standby generator?
For pure backup, a battery is not the only option. Here is how it compares with a standby generator:
| Compare | Battery | Standby generator |
|---|---|---|
| Runtime | Limited by stored energy; solar can extend it | As long as fuel lasts |
| Noise and emissions | Silent, none on site | Engine noise and exhaust |
| Daily use | Can store solar every day | Only runs in outages and tests |
| Maintenance | Very little | Regular servicing and exercising |
| Cold weather | Check charging and capacity limits | Needs cold-weather starting provisions |
Some households combine them, or use a portable generator with a transfer switch for long outages. The right answer depends on how often outages happen where you live, how long they last and what you need to keep running.
Approvals and next steps
A battery installation needs an electrical permit. If it is connected to a solar system or can export to the grid, your wire owner may also need to be notified under the micro-generation process. See Alberta micro-generation explained.
If you are planning solar, decide early whether a battery might follow. Some inverters work with batteries and some do not. See how to size a home solar system. Our battery storage team can design backup around your critical loads and your panel.
Common questions
Will a battery keep my whole house running in an outage?
Usually only the critical circuits. Whole-home backup is possible with enough capacity, but heavy loads like electric ranges and EV chargers drain a battery very quickly.
Can I add a battery to my existing solar system?
Often, yes. The approach depends on your inverter. Some systems add a battery with its own inverter on the AC side; others need equipment changes. We check compatibility first.
Does a battery work in a cold garage?
It depends on the battery's ratings. Many lithium batteries need built-in heating to charge below freezing. Location and temperature are part of the design.
Will a battery save me money in Alberta?
It can, depending on your retail plan and how you use energy, but for most households backup is the main benefit. Be cautious of savings claims that do not show their assumptions.
Codes and permit rules change and every building is different. For work on your system, talk to a licensed electrician and your local permit authority.