How Many Solar Panels Do You Actually Need? A Real Answer
Online solar calculators give you a number in seconds. Here's why that number is usually wrong, and what an accurate system size actually depends on.
Search "how many solar panels do I need" and you'll get a calculator that asks for your zip code and average bill, then spits out a panel count in seconds. The number it gives you is a rough starting point at best — and on a lot of roofs, it's meaningfully wrong.
Accurate system sizing starts with your actual utility usage, not your average bill. A household with the same average monthly bill as their neighbor can have a completely different usage curve — more usage in evening hours, a pool pump running midday, a home office pulling power on a different schedule. We pull 12 months of interval usage data from your utility, not just a bill total.
The second variable a quick calculator can't see is your roof itself: orientation, pitch, and shading from trees, chimneys, or neighboring structures. Two identical roofs a block apart can have meaningfully different production potential because of a single mature tree.
The third variable is what you're actually optimizing for. Some households want to offset 100% of usage; others want to offset the majority while keeping the system size (and cost) down; some are sizing specifically around an upcoming EV purchase or a planned addition. The 'right' system size depends on which of these you're solving for, not a single universal target.
A calculator that skips all three of these and gives you a confident number in ten seconds isn't saving you time — it's setting you up for a system that's undersized for your actual usage, or oversized in ways that don't pay back. A proper site analysis (see our solar analysis service) takes longer than ten seconds because it's actually looking at your situation.