Three topologies dominate residential solar, and the difference between them is not the panels — it is what the inverter does when the grid fails, and how much of your consumption you intend to cover. Pick the wrong one and you either lose backup you assumed you had, or you pay for capability you never use.
The one-line summary
- Grid-tied (no battery) — cheapest, no backup, exports surplus.
- Hybrid (grid-tied + battery) — battery-backed, keeps selected circuits running in a blackout, can still export.
- Off-grid — no grid connection at all; the battery and generator are your only supply.
Comparison table
| Grid-tied | Hybrid | Off-grid | |
|---|---|---|---|
| Works during blackout | No | Yes (backed-up circuits) | Yes (always) |
| Battery required | No | Yes | Yes (large) |
| Exports surplus to grid | Yes | Yes, if permitted | N/A |
| Battery capacity needed | None | 5–20 kWh | 20–60+ kWh |
| Generator backup | Rarely | Often | Usually essential |
| Upfront cost | Lowest | Medium | Highest |
| Best for | Reducing bills | Bills + resilience | No grid available |
Grid-tied systems
Panels feed a grid-tied inverter that synchronises with the utility and pushes energy into the house, exporting any surplus. There is no battery, so the system is the cheapest per watt and the fastest to pay back where export tariffs or net metering exist.
The limitation that surprises people: a standard grid-tied inverter shuts down during a blackout. It must, by design and by law — feeding power into a de-energised line would endanger utility workers repairing it. So on a sunny day with a grid outage, a grid-tied system produces nothing.
Hybrid systems
A hybrid inverter manages three sources at once: solar panels, the battery, and the grid. It can charge the battery from solar or from cheap off-peak grid power, discharge it to the house when tariffs are high, and — critically — isolate the house and form its own local grid during an outage.
That last capability is called an EPS (Emergency Power Supply) or backup output. It is not automatic on every inverter, and it usually serves a dedicated sub-panel of critical loads rather than the whole house. When you design the system, decide which circuits matter: refrigeration, lighting, internet, a few sockets, maybe one air conditioner.
Hybrid is the right default for most homes with a grid connection that is unreliable or expensive. Explore the configuration on our home energy storage system page.
Off-grid systems
Off-grid means the utility is not part of the design at all. Everything the house consumes must be generated, stored, or produced by a generator. This drives a completely different sizing exercise:
- Larger battery bank — you must cover several consecutive low-sun days, not just one evening.
- Larger array — winter output, not annual average, sets the array size.
- Generator — the practical insurance policy for the worst week of the year; without one you either massively oversize the battery or accept outages.
- Load discipline — resistive heating, electric cooking and tumble dryers are expensive to run off-grid and are usually replaced by gas or heat pumps.
Off-grid makes sense where a grid connection is genuinely unavailable or where the connection cost exceeds the system cost. It is rarely justified purely on economics in a serviced area.
How to choose
- How bad are your outages? None → grid-tied. Occasional and short → hybrid with modest capacity. Frequent or long → hybrid with a large bank, or off-grid.
- Is there a grid connection at all? No → off-grid, and size for your worst week.
- What is your tariff structure? Large peak/off-peak spread → hybrid pays for itself through arbitrage as well as backup.
- What must never go off? Medical equipment, security systems, well pumps, home office — these define your critical-loads sub-panel and therefore your minimum battery size.
Battery chemistry and capacity by topology
All three topologies benefit from LiFePO4, but for different reasons. Hybrid and off-grid systems cycle daily, so cycle life and depth of discharge dominate — LiFePO4's 6,000+ cycles and 80%+ usable depth are exactly what daily cycling demands. Grid-tied systems without storage have no battery to choose.
Capacity guidance: hybrid systems for bill savings typically run 5–10 kWh; hybrid systems sized for real resilience run 10–20 kWh; off-grid houses commonly need 20–60 kWh depending on climate and generator strategy. Our residential range is configurable across this span — see how to size a home energy storage system.
FAQ
Only if you have a hybrid inverter with a backup (EPS) output and a battery. A standard grid-tied inverter must shut down during an outage for safety, so panels alone will not power the house.
Yes. This is called retrofitting, and it usually means adding a hybrid inverter or an AC-coupled battery inverter alongside your existing grid-tied inverter. Send us your inverter model and we will confirm compatibility.
Rarely, if a grid connection already exists. Off-grid requires a much larger battery and array plus a generator, which normally exceeds the cost of a grid connection plus a hybrid system.