How home solar actually works
From the sun on your roof to the plug in your wall, here's the plain-language version of how a modern solar system powers a South African home, cuts your Eskom bill and keeps you running through load-shedding.
How power moves through your home
A solar system does the same thing every sunny day, in the same order. Once you see the loop, the whole thing makes sense.
Panels turn sunlight into electricity
Solar panels on your roof are made of photovoltaic (PV) cells. When daylight hits them they generate direct current (DC) electricity — even on overcast days, just less of it. The more panels and the better the sun, the more power you make.
The inverter converts DC into usable AC
Your home, appliances and plugs all run on alternating current (AC). The inverter is the brain of the system: it converts the panels’ DC into 230V AC, matches it to the grid, and decides moment-to-moment where the power should go.
Your home uses it first, cutting grid draw
That solar power flows straight to whatever is switched on — the geyser, fridge, pool pump, aircon. Every watt you make and use is a watt you don’t buy from Eskom or your municipality, so your daytime consumption drops first.
Surplus charges the battery or feeds back
When you’re making more than you’re using, the extra tops up your battery so you have stored power for the evening and for outages. If the battery is full and your setup allows it, the surplus can feed back to the grid under an approved feed-in arrangement.
Curious what this looks like as a real package for your roof? Compare solar power systems and packages for your home, see the solar solutions we arrange or run the numbers with our savings calculator.
The four parts of a system
Almost every home solar setup comes down to these four pieces working together. Here's what each one does and why it matters for your bill and your backup.
Solar panels
What it does: Mounted on your roof, they capture sunlight and produce DC electricity throughout the day.
Why it matters: They are your generator. Panel count and orientation set the ceiling on how much energy your system can make, which drives how much of your bill you can wipe out.
Inverter
What it does: Converts DC to AC, manages the flow between panels, battery, home and grid, and keeps everything in sync and safe.
Why it matters: A hybrid inverter is what lets you store power and run through an outage. Its size (kW rating) determines how much you can run at once.
Battery
What it does: Stores surplus daytime solar as chemical energy, usually in a lithium (LiFePO4) battery, and releases it on demand.
Why it matters: The battery is what carries you into the evening and through load-shedding. More storage means longer backup and less reliance on the grid after dark.
Grid connection
What it does: Your existing municipal or Eskom supply stays connected to a grid-tied or hybrid system and acts as a backstop.
Why it matters: It tops you up on dull days or heavy-use evenings, and a registered (SSEG) connection can let you feed surplus back where the municipality allows it.
Solar power, solar energy and a solar system
People use these interchangeably, but they answer different questions. Solar power usually means the electricity being produced at a moment in time. Solar energy is the broader idea of energy from the sun. A solar system (or solar home system) is the equipment that makes it useful at home: panels, inverter, battery, protection equipment, mounting and the connection to your circuits.
That matters when you compare quotes. The panel count tells you about generation, the inverter rating about how much can run at once, and the battery capacity about how much can be stored. None of those numbers alone describes the whole result.
kW vs kWh
kW (kilowatts) is power: how much you are drawing right now, like the width of a tap. kWh (kilowatt-hours) is energy over time, like the water in the bucket.
Inverters are rated in kW, which decides whether the kettle and microwave can run together. Batteries and your electricity bill are measured in kWh, which decides how long you last through an outage. Our appliance power table gives both numbers for 20 common appliances.
What happens during load-shedding
This is the part most South Africans care about most. Whether the lights stay on comes down to one thing: do you have a battery?
- The battery takes over instantly. When Eskom cuts the grid, a hybrid inverter switches your home onto stored battery power in a fraction of a second, fast enough that most people don't even notice the changeover.
- Sub-second switchover. Sensitive electronics like computers, TVs and Wi-Fi routers keep running without a reboot, because the gap is far shorter than with a generator that has to start up.
- By day, solar keeps topping up. If load-shedding hits while the sun is out, your panels can run the house and recharge the battery at the same time, stretching your backup further.
Solar-only has no backup
It surprises a lot of people: a grid-tie system with panels but no battery actually switches off during load-shedding. For safety, the inverter is required to shut down when the grid is dead, so it can't back-feed the lines while technicians work.
So panels alone will lower your bill, but they won't keep the lights on in an outage. If backup through load-shedding is the goal, you need a battery — which is exactly why the hybrid setup is the most popular choice in South Africa.
See backup-ready systemsHow a home solar system runs from morning to night
You don't push any buttons. The inverter decides, second by second, whether your home runs on solar, battery or grid.
Morning
Panels start producing as the sun comes up. That power runs whatever is on right then, such as the kettle, the Wi-Fi router and the fridge, and anything left over starts charging the battery.
Midday
Production peaks. The panels usually make more than the house uses, so the surplus fills the battery. Once it is full, a registered system can export the extra where your municipality allows it.
Evening
The sun sets and the panels stop. The house runs on the battery instead: lights, TV and cooking on energy banked earlier in the day. When the battery reaches its set reserve, the grid takes over.
Load-shedding, any time
A hybrid system keeps running on solar and battery when the grid drops. During the day the panels can run the house and recharge the battery at the same time.
What the monitoring app shows. Every modern system comes with an app that shows this in real time: arrows from panels to home, home to battery or grid to home. Once you know the four parts, you can watch the battery charge on a sunny afternoon or spot an appliance quietly using more than it should.
Comparing the money side first? Our solar panel prices guide and battery price comparison explain why a panel-only or battery-only number can't be compared with a complete installed system, and the Solar Price Index tracks installed-system prices each quarter.
Grid-tie vs hybrid vs off-grid
Three ways to configure a system, from cheapest to most independent. Most homes land on hybrid: savings during the day, backup at night.
Grid-tie (no battery)
Panels and an inverter feed your home while the sun is up, trimming your daytime bill. It’s the cheapest way in, but with no battery it switches off during load-shedding, so you get savings without backup.
Hybrid (panels + battery)
The most popular choice in South Africa. You save during the day, store surplus for the evening, and keep essential circuits running through outages. It balances savings and backup, and can still draw from the grid when needed.
Off-grid
Fully independent, with no municipal connection at all. It needs generous panels and battery capacity to cover every season and every cloudy stretch, which makes it the most expensive. Usually reserved for remote sites without a reliable grid.
Not sure which fits your roof and budget? Browse the equipment brands we work with, or tell us about your home and we'll help you match a system to how you actually use power.
How solar works: common questions
Does solar power work when there is no sun?
Panels produce much less on heavily overcast days and nothing at night. That is what the battery is for: it stores daytime energy so you still have power after dark or in bad weather. On a hybrid system the grid is the final backup.
Will solar keep my home running during load-shedding?
Only with a battery and a hybrid or off-grid inverter. A grid-tie system without a battery shuts off during a blackout for safety, even in bright sunshine, so it cannot back-feed the lines while technicians work.
What is the difference between kW and kWh?
kW (kilowatts) is power: how much you are drawing at this moment. kWh (kilowatt-hours) is energy: how much you use over time. Inverters are rated in kW, while batteries and your electricity bill are measured in kWh.
What is the difference between solar power, solar energy and a solar system?
Solar power usually means the electricity being produced at a moment in time. Solar energy is the broader idea of energy from the sun. A solar system is the equipment that makes it useful at home: panels, inverter, battery, protection, mounting and the connection to your circuits.
Do I need to understand all of this to go solar?
No. A good installer handles the design, sizing and setup. Knowing the four parts helps you ask better questions, spot a quote that does not add up and read your monitoring app.
SolarGuide is an independent referral partner. Alumo supplies, installs, finances and warrants the systems. Any pricing is indicative and subject to a site assessment and credit approval.
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