Off-grid, hybrid or backup — which home energy system is right for you?

Before you compare batteries or inverters, there is a more basic decision to make: what job is the system actually for? A home energy system can do three very different things — run a house with no grid at all, work alongside the grid so you use more of your own solar, or sit quietly in reserve and take over when the power fails. Those are the off-grid, hybrid and backup scenarios, and choosing the wrong one is the most expensive mistake in the whole project.

This guide defines the three, shows who each is for, and walks through the equipment, cost and complexity differences — from a European starting point, where the grid, the electricity price and the subsidy landscape all shape the answer.

Not sure which one you are? Answer a few questions and our system designer picks the right setup for you — off-grid, hybrid or backup — then sizes the storage, inverter and solar to match. About two minutes, no obligation.

The one question that decides everything

Everything starts with your relationship to the grid. Ask yourself two things:

1. Do you have a reliable grid connection at all?
2. If you do, what do you want the battery to achieve — a lower bill, or protection from outages?

Your answers place you in one of three scenarios. Everything after that is engineering.

Off-grid: the battery is the grid

What it means. There is no utility connection, or one so weak or costly that you treat it as if it were not there. The system is your sole source of power, so it must generate its own energy — solar, sometimes with a generator behind it — and store enough to carry the house through cloudy days and long nights.

Who it's for:

• Properties with no mains connection at all — remote cabins, mountain huts, farms and agricultural buildings, island homes.
• New builds where bringing in a grid connection would cost more than a generation-plus-storage system.
• Locations with a grid so unreliable that people already live around the outages — weak-grid rural and island regions.

How it's configured. Solar is not optional here; it is the only daily source of energy. Storage is sized around days of autonomy — we plan for roughly 1.5 days as a baseline so a single dull day does not black out the house, and more if you intend to winter off-grid. For the same house, this is the largest battery of the three. You also need an inverter that can build and hold its own stable AC "island" without a grid to lean on. A complete off-grid solar system matches panels, inverter, storage and balance-of-system from the start — which matters most here, because there is no grid behind it to paper over a mismatch.

The honest part. Off-grid is the most demanding scenario: the biggest storage, real seasonal planning, and usually a generator kept as a last resort for the darkest weeks of the year.

Hybrid: keep the grid, use more of your own solar

What it means. Grid-tied by design. Solar charges the battery and powers the house by day; the battery covers the evening; the grid fills any shortfall and — where the rules allow — absorbs surplus. The goal is self-consumption: using as much of your own generated energy as you can, instead of buying it back at the retail price.

Who it's for:

• Homeowners with a stable grid and a solar array (or plans for one) who want to cut their electricity bill.
• Households facing high retail prices and shrinking feed-in tariffs — the exact European situation today, where a kWh you use yourself is worth far more than one you export.
• Anyone who wants some outage protection as a bonus, without paying to size for full independence.

How it's configured. Solar is strongly recommended, but it is your choice — even without it, the battery earns its keep by shifting cheaper energy into expensive evening hours. Storage is sized to bridge roughly one day/night cycle, not days, so it is markedly smaller than an off-grid bank for the same house; a single Storage Wall series unit often covers it. A hybrid inverter ties solar, battery and grid together and decides, minute by minute, what to store, use and draw.

This is the mainstream European choice. More than a third of new residential solar installations now pair with storage, precisely because self-consumption beats export.

Backup: a stable grid, protected against outages

What it means. Your grid is reliable and your price is tolerable, so you are not trying to leave it or heavily self-supply — you simply do not want to be in the dark (or lose the freezer, the heating controls, the home office) when it drops. The battery sits in reserve and takes over the moment the grid fails.

Who it's for:

• Homes in stable-grid regions — most of Western Europe — that still see the occasional storm or planned outage.
• Households with a few critical loads that must never go dark: refrigeration, medical equipment, heating controls, routers, a home office.
• People who want the simplest, lowest-cost way into home storage.

How it's configured. Storage is sized in hours, not days — you decide how long you want to ride through an outage, and the battery is sized to that fraction of a day. That makes it the smallest and cheapest of the three; a compact Storage Wall series unit is often enough. Solar is optional — a backup battery charges perfectly happily from the grid. The one requirement is an inverter that can disconnect from the grid on failure and keep your protected circuits live.

The equipment differences at a glance

All three use the same LiFePO4 chemistry and the same usable 0.9 depth of discharge, and the sizing arithmetic is identical — only the autonomy target changes. That is why the same house can need three very different batteries.

Cost and complexity: the honest trade-off

The three line up neatly from lightest to most demanding. Backup is the smallest lift — a modest battery, an inverter that can carry your protected circuits, no obligation to add solar. Hybrid steps up: you add (or already have) a solar array and a self-consumption strategy, and the battery is larger because it works every single day rather than only during outages. Off-grid is a genuine engineering project — the largest storage, a generation source you cannot skip, seasonal planning, and usually a generator in reserve.

A concrete feel for the gap: take one house using about 12 kWh a day. As a backup system for a few hours of critical load it needs only a few kWh of storage; as a hybrid it needs on the order of 13 kWh to bridge a day/night cycle; off-grid with 1.5 days of autonomy it needs around 20 kWh. Same house, same consumption — the scenario alone multiplies the battery.

Don't want to judge this by eye? Tell our system designer about your site and your goal, and it picks the right setup for you and sizes it — battery, inverter and solar — in about two minutes.

How to tell which one you are

A short decision path:

• No grid, or a connection that would cost a fortune to bring in → you are off-grid. Budget for solar, days of storage and a seasonal margin.
• Reliable grid, and you want to cut your bill with your own solar → you are hybrid. This is the default for most European homes with a usable roof.
• Reliable grid, prices you can live with, you just fear the outages → you are backup. Start small; you can always grow later.

And you are not locked in. A hybrid system already gives you outage protection as a side effect, and plenty of homes start as backup or hybrid and add capacity as needs — a heat pump, an EV — arrive.

The European angle

• Prices. Retail electricity in Europe is among the highest anywhere, and the gap between what you pay to import and what you are paid to export has widened. That single fact pushes most grid-connected European homes toward hybrid self-consumption rather than pure export.
• Grid. Western European grids are largely stable, which is why backup here is about the occasional storm or planned works, not daily survival. In weak-grid or unconnected locations — some rural, island and agricultural sites — off-grid is not a lifestyle choice but a necessity.
• Sun. Location changes the solar side sharply. A kilowatt-peak in southern Spain (4.5 peak sun hours per day) yields far more than the same panels in Germany (3.0) or the UK (~2.5) — which is why off-grid is easier to run in the south, and why northern off-grid systems need bigger arrays, more storage and a winter fallback.
• Rules and incentives. Grid-connection rules and subsidies vary by country and change often. They tilt the economics, but they rarely change which scenario you are. Decide the scenario first, then optimise the numbers inside it.

The short version

Off-grid, hybrid and backup are not three products — they are three jobs. Off-grid replaces the grid and needs the most of everything. Hybrid works with the grid to use more of your own solar and lower your bill — the mainstream European choice. Backup keeps a stable grid honest by covering outages, and it is the simplest place to start. Decide the job first; the equipment follows.

Or let the tool do it: tell the Senneon system designer about your site and your goal, and it picks the right setup for you and returns a complete, sized, indicative design — battery, inverter and solar — ready to send to us for a quote.