These solve two different problems. Most homeowners want one; a small number genuinely need the other.
Grid-tied: solar plus a very large, free battery
A grid-tied system exports excess production to the grid and draws back from it at night or on cloudy days, effectively using the grid as storage — that's what net metering credits are. This is dramatically cheaper than battery storage sized to cover every gap, which is why the vast majority of residential solar installations are grid-tied.
The tradeoff: without battery backup, a grid-tied system typically shuts off during a grid outage for safety, even if the sun is shining — a common surprise for new solar owners expecting backup power by default.
Off-grid: complete independence, complete responsibility
An off-grid system has no utility connection at all — every watt-hour used has to come from what the system generated and stored itself, sized with enough battery and panel capacity to get through your worst realistic weather stretch. This is dramatically more expensive per usable watt than grid-tied, since the system has to be sized for worst-case conditions rather than relying on grid backup. See our off-grid system calculator for what that sizing actually looks like.
Who actually needs off-grid
Off-grid makes sense primarily where there's no practical grid connection available — remote cabins, rural land, or where the cost of extending utility lines exceeds the cost of a self-sufficient system. For anyone with an existing grid connection, off-grid is rarely the economical choice purely on cost.
The middle ground: grid-tied with battery backup
A grid-tied system with battery storage gets most of grid-tied's economics while adding backup power during outages — the battery kicks in automatically rather than needing to size for worst-case weather like a true off-grid system. This is increasingly the choice for homeowners who want both net metering economics and outage resilience. Compare the numbers with the battery ROI calculator and battery vs generator comparison.
Frequently asked questions
Does a grid-tied solar system work during a power outage?
Not by default — most grid-tied systems automatically shut off during an outage for utility worker safety, unless the system includes battery storage with an automatic transfer switch designed for backup operation.
Is off-grid solar cheaper than paying to extend utility lines to remote property?
It can be, depending on distance — utility line extension costs can run into tens of thousands of dollars for remote properties, at which point an off-grid system sized properly for the home's needs may be more cost-effective.