Pick your target payback period. We'll show the system size and the prices to shop for.
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Pool usage
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1 kWh/day8 kWh/day
EV charging usage
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2 kWh/day15 kWh/day
Workshop usage
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1 kWh/day6 kWh/day
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5 yrs10 yrs
What if I get more or less solar?
Solar
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Battery
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What if I get more or less expensive solar?
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Payback, solar size, battery size, solar price and battery price are all linked. Move any one and the others follow.
Payback period
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Saves per month
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Common questions
Panels are sized to cover your everyday base load plus your evening appliance use, based on your city's average sun hours. Battery is sized separately, using only your evening and night usage, since that's the part that needs to be stored rather than used straight from the panels.
Panels and battery solve different problems in reality — panels supply daytime power, battery covers evening and night power — and their prices move independently in the market. Locking them together would misrepresent how real quotes actually work.
It's meant to represent an all-in installed cost per kilowatt — panels, inverter, mounting and labor — not just equipment. When you compare it to a real quote, check the installer's number covers the same things.
No. Rebates and incentives vary hugely by country, region and even by year, so every figure here is before any incentive. Your real cost could end up lower once local schemes are applied — worth checking what's currently available where you live.
It's a reasonable planning estimate, not survey-grade data — actual output also depends on your roof's angle, shading and orientation. Treat the payback number as a solid starting point for shopping, not a guarantee.
Extra loads add to your evening usage, which increases the battery size needed to cover them — and battery is the more expensive component per unit of capacity. More usage generally means more cost before it means more savings.
Solar and battery only save you money up to what you actually use. Oversizing either one past what you need still helps a little, but with fast diminishing returns, since there's nowhere useful for the surplus to go.
Currency and typical pricing are localized for the US, Canada, Australia, UK and Germany, based on real market data. Everywhere else uses a general estimate in US dollars, clearly labeled, since reliable public pricing isn't yet available for every market.
That's the goal — the number is a target to shop and negotiate toward, not a guaranteed price. If every quote comes back higher, that's useful information too: it tells you your target payback period needs to stretch out a little.
Bigger panels mainly mean more daytime power and lower bills, while more battery mainly means longer backup and better evening savings. Sizing them independently lets you see which lever actually matters most for what you personally want.