Will Solar Keep My Power On During a Brownout?
This is the most expensive misunderstanding in residential solar. Someone installs a grid-tied system, the power goes out, and they're standing under a roof full of panels in blazing sunshine with no electricity in the house. It feels like a scam.
It isn't. The system is doing precisely what it's built to do.
Why it switches off
A grid-tied inverter syncs with the utility supply and pushes power into it. When the grid dies, the inverter has to disconnect within a fraction of a second. It's called anti-islanding protection and it's a safety requirement, not a shortcoming.
The reasoning is simple enough. Crews restoring a line need that line dead. If thousands of rooftops kept feeding a circuit that had supposedly been switched off, the line would be live with nobody having energised it.
If anybody offers to disable anti-islanding so your on-grid system keeps running through an outage, say no. It puts linemen at risk and it will fail inspection.
What actually keeps the lights on
Two things: stored energy, and an inverter capable of forming its own grid. Together that's a hybrid system.
When the utility drops, a hybrid inverter opens a transfer switch, isolates your house from the network, and carries on supplying your circuits from the battery and whatever the panels are making. Because the house is now electrically separate, nothing gets exported and the safety problem never arises.
Changeover is usually quick enough that you'd only notice the lights blink. If you need genuinely uninterrupted supply for sensitive equipment, say so early, because that's a stricter requirement than ordinary backup and it changes the design.
Deciding what to back up
You don't need to back up the whole house and usually shouldn't. Backup circuits get chosen deliberately and the battery is sized to them.
| Load | Rough draw | Usually backed up? |
|---|---|---|
| LED lighting | Tens of watts | Yes |
| Refrigerator | 100–200 W average | Yes |
| Electric fans | 50–80 W each | Yes |
| Router, phones, laptops | Small | Yes |
| Inverter aircon | Several hundred W up | Sometimes, one unit |
| Water heater, electric oven | Very high | Rarely worth it |
| Water pump | Big surge on start | Often, if sized for the surge |
Two things worth knowing. Motors — pumps, compressors, older aircon — pull a large surge when they start, and the inverter has to handle that surge, not just the running load. And the useful question isn't "what would I like to keep on?" It's "what costs me money or safety if it's off for four hours?"
What about just buying a generator?
Cheaper to buy, more annoying to live with. Fuel, noise, fumes, going outside in the rain to start it, and servicing whether you used it or not. A battery is the reverse: more upfront, silent, automatic, no fuel.
They're not mutually exclusive either. Sites that genuinely can't lose power, cold storage and some clinics, sometimes run a hybrid for instant changeover with a generator behind it for multi-day events.
Be clear-eyed about the return
A battery rarely pays for itself through bill savings. What you're actually buying is continuity. Stock that doesn't spoil, a shop that keeps trading, a work-from-home day that isn't lost, a house that isn't dark at 8pm with a baby in it. Whether that's worth the money depends on how often your area really loses power and what an outage costs you when it does.
If outages where you are are short and rare, plain on-grid is probably better value. If they're a weekly fact of life, the battery is the entire point of the exercise.
If brownouts are the reason you're reading this
Then the question isn't really whether to go solar. It's how much of your house you want still running at eight in the evening when the line drops, and what that's worth to you.
Tell us which circuits you can't afford to lose and we'll size a hybrid system around them. Message us on Messenger, call, or come and see the battery banks and hybrid inverters at our shop in Concordia, Bolinao — it's a lot clearer in person.