Are solar panels and a home battery actually worth it?
It depends almost entirely on how much of the generated electricity you use yourself, because the value of a unit you consume is far higher than the value of a unit you export — and that single ratio determines the payback more than panel efficiency or system size.
The economics, stated plainly. Electricity you use is worth what you would otherwise have paid to import it. Electricity you export is worth the export rate, which is typically much lower. A household that is out all day and generating at midday exports most of it and captures little value.
What actually improves the return:
Self-consumption. Shifting usage into daylight — washing, dishwasher, hot water, EV charging — is the highest-value action and costs nothing.
A battery, which stores midday generation for evening use, raising self-consumption substantially. Its own payback is more marginal, because batteries are expensive and degrade, but it improves considerably when combined with a time-of-use tariff that lets you also charge cheaply overnight and avoid peak rates — at which point the battery earns money even without solar.
A diverter, sending surplus to an immersion heater rather than exporting it.
What determines generation: roof orientation, with south best and east-west spreading output across the day, which can suit self-consumption better despite a lower total; pitch; shading, where even partial shading can disproportionately affect a string, addressed with optimisers or microinverters; and panel degradation of a fraction of a percent per year.
The costs beyond installation: an inverter replacement during the system's life, which is a real and frequently omitted cost; scaffolding; and any roof work needed first — never fit panels to a roof approaching the end of its life.
The practical checks: confirm the export arrangement and rate before installing; check your consumer unit and roof structure; use a certified installer, since that is required for export tariffs; and treat any quote's payback figure sceptically, since assumptions about future prices drive it entirely.
General information, not financial advice.