What solar power can and cannot do for a house
Solar power for a home works as a daytime generator beside the grid: the house uses what the panels make, the surplus is exported where the utility allows it, and the grid covers nights, winter evenings and cloudy spells. It lowers purchased electricity but rarely replaces the grid completely.
Where does the solar power go during a day?
Follow a sunny summer day. Early morning, the panels make little and the house draws mostly from the grid. By midday output is high, and whatever the house is running, from the fridge to a dishwasher, is fed first by the panels. If production exceeds use, the extra flows out through the meter. In the evening, output falls and the grid takes over again.
That daily shape explains a lot. A household that is empty from eight to five uses less of its own solar power directly, and exports more. A household with someone home, or with a heat pump and an electric vehicle, uses more on site. The share of production you consume yourself is called self-consumption, and it matters because exported power is usually credited at different terms than power you avoid buying.
What happens to the surplus power?
Utilities handle surplus differently. Some credit exports against future bills under net metering, some pay a set rate, and some apply a mix that has changed over time. Provinces have also changed their rules, so check the terms that apply to you at the moment you apply, not a summary from a website. For Alberta, see Alberta net metering explained and the Alberta microgeneration regulation.
Ask your utility three things: how exports are credited, how long credits last, and whether fees apply to your size of system. The answers can change what a system is worth to you, and they are part of any honest payback calculation, as in solar panel payback period.
Will solar power keep the lights on in an outage?
Not by default. A standard grid-tied inverter shuts down when the grid goes dark, which protects line workers from back-feed. To keep power on you need a system designed for it: usually a battery, a backup-capable inverter and a separate circuit for the loads you want to keep running, like the fridge, lights and furnace fan. Even then, a battery limits how long and how much.
Read what a solar system does in a power outage and solar battery storage in Canada before paying for backup you may not need. A fully independent setup is a different design, covered in grid-tied versus off-grid solar.
How do you get more value from your solar power?
- Shift flexible loads to daytime. Run laundry, dishwashers and water heating when the sun is up.
- Pair solar with electric heating. A heat pump uses electricity efficiently; see the cold-climate heat pump guide.
- Charge an electric vehicle in the day, if possible.
- Watch your production. Monitoring shows underperformance early; what to track lists the signals.
- Keep panels clear. See solar panels and snow removal before climbing a roof.
Winter is the weak point, since January output is a small fraction of June output while heating demand is at its highest.
Can solar power ever supply a home's heating?
Electric solar can contribute, but the winter gap is hard to close. Drake Landing in Okotoks, Alberta, took another approach: it collected summer solar heat and stored it in boreholes, so that 52 homes could draw on it in winter. The homes page shows what a house in that community looked like, and the solar space heating guide explains the idea for ordinary houses.
Quick answers
Can solar power run a whole house?
Over a year it can offset a large part of a home's electricity, but the home normally stays on the grid for nights, winter and cloudy weather unless it is designed as an off-grid system with storage.
What happens to extra solar power I do not use?
It is usually exported to the grid and credited under your utility's terms. Credit rules vary by province and utility, so check them before you sign a contract.
Do solar panels work during a power outage?
Not in a standard grid-tied system, which shuts off for safety. A battery and a backup-capable inverter are needed to keep selected circuits running.
How can I use more of my own solar power?
Run flexible loads during the day, add electric heating or an electric vehicle charged in daylight, and consider a battery if exports are credited poorly.