When the lights go out in January, the question is not which technology is more fashionable. It is which one keeps the furnace fan turning and the pipes from freezing for as long as the outage lasts. Batteries and generators solve that problem in very different ways, and for many homes the best answer uses a bit of both. This article sits in our batteries and backup power hub, where you will find companion guides on cost and sizing.
The starting point: solar alone will not help
A common surprise for new owners is that a grid-tied solar system goes dark in an outage even on a bright day. The inverter is built to shut down when the grid fails (called anti-islanding), so that it does not push power onto lines where crews may be working. If you want panels to keep supplying the house, you need a battery system capable of backup operation. The basics are covered in solar battery storage basics.
How the two options compare
| Factor | Battery (with solar) | Generator |
|---|---|---|
| Switch-over | Often within a second or so on backup-capable systems | Manual start, or automatic with a transfer switch after a short delay |
| Runtime | Limited by stored kWh; solar can extend it by day | As long as you have fuel |
| Noise and fumes | Silent, indoors or in a garage | Loud, and exhaust must stay outdoors |
| Upfront cost | Several thousand dollars up to well over ten thousand | Portable units cost far less; standby units cost more |
| Running cost | Close to none | Fuel, oil, servicing |
| Maintenance | Minimal, mostly software | Regular test runs, stale fuel, wear |
| Cold weather | Performance drops in deep cold, so placement matters | Cold starts can be hard without good maintenance |
Prices vary widely by region and model, so use the table as a direction rather than a budget.
Runtime is the big difference
A battery stores a fixed amount of energy. A 10 kWh battery supplying a fridge, some lights, a router and a furnace fan at an average of 400 watts would last roughly a day, give or take. Run an electric range or baseboard heaters and the same battery empties in a few hours. The calculation is simple, and our guide on how to size a home battery walks through a worked example.
Solar can refill the battery during the day, which turns a short outage into an indefinite one in summer. In winter the picture changes. Days are short, the sun is low, and snow may cover the array. Winter performance is better than many people expect on clear days, but a week of grey weather will not recharge a battery much. That is where a generator earns its place.
A generator, by contrast, simply runs while there is fuel. A tank of gasoline, propane or diesel can carry a household for days if you ration it. The trade-offs are real: you need to store fuel safely, rotate it so it does not go stale, run the unit monthly, and keep it well away from windows and doors. Carbon monoxide from indoor or near-window generators kills people every year during outages, so this is not a detail to skip.
Comfort and convenience
Many owners value a battery for how little it asks of them. At 3 a.m. in a snowstorm there is no pull-cord, no fuel can in the dark, no neighbour complaining about the noise. The house simply carries on, usually with a short app notification. You can also use a battery daily for time-of-use savings in some provinces, which a generator cannot do.
A generator is better when the load is large and the outage is long. Electric resistance heating, a well pump with a big motor, or a workshop can overwhelm a home battery’s power rating (kW) or drain its energy (kWh) fast. A generator sized for the job handles those without drama.
Cost, honestly
A battery installed with solar commonly adds several thousand dollars and can pass ten thousand for larger systems, as discussed in our home battery cost guide. A portable generator with a safe inlet and interlock arrangement costs a fraction of that. If your only goal is surviving two or three outages a decade, the generator is usually cheaper. If you also want bill savings, quiet and automation, the battery gains ground.
Whatever you choose, have the installation done by a licensed electrician and permitted as required. A portable generator should never be plugged into a house outlet to “back-feed” the panel. Use a proper inlet and interlock or transfer switch installed to the electrical code, and look for CSA certification marks on equipment.
A practical middle path
Plenty of Canadian households end up with a modest battery covering essentials for the first day, backed by a small generator for the rare multi-day event. Decide which loads truly matter, estimate how long outages usually last where you live, and size from there. If you are not sure where to begin, a home energy audit will reveal which loads are the real energy hogs, and cutting those can shrink whichever system you choose.
Quick answers
Will my solar panels work during a power outage?
Not with a standard grid-tied system. The inverter shuts down when the grid fails, to protect line workers. You need a battery system that can run in backup mode to keep using solar power.
How long will a battery power my house?
It depends on stored energy and what you run. A 10 kWh battery powering a fridge, lights and internet could last a day or more, while electric heating or an oven would drain it in hours.
Can I run a generator and solar together?
Only with equipment designed for it and a proper transfer arrangement installed to code. Never back-feed a house panel from a portable generator through an outlet.
Where to verify
Rules and prices change. Confirm current details with the official bodies below.