How to read your electric bill for solar
Before you can size solar, you need to understand your own electric bill — and most of us never look past the amount due. The good news: a handful of lines tell you almost everything. Here's what to find and why it matters.
The one number that matters most: kWh
Kilowatt-hours (kWh) measure the total energy you used. This is the figure that sizes a solar system — not the dollar total, which changes with rates and fees. Look for "kWh used" or "usage" on the statement.
- Grab twelve months of kWh and add them up (or use the annual total many utilities print).
- A typical US home uses 10,000 to 12,000 kWh per year.
That annual number feeds straight into sizing — see how to size a residential solar system.
Your rate: what a kWh costs
Divide the energy charges by the kWh used, or read the per-kWh rate on the bill. Watch for:
- Tiered rates — the price rises after you cross a usage threshold. Solar shaves off the most expensive top tier first, which is where savings are biggest.
- Time-of-use (TOU) — power costs more at peak hours (often late afternoon and evening). This affects whether a battery is worth it.
- Seasonal rates — summer often costs more than winter.
Demand charges (read the fine print)
A demand charge bills you for your single highest burst of power (measured in kW), not total energy. If you see one, note it: solar can lower total kWh a lot but may barely touch a demand charge, since your peak can happen after sunset. Demand charges are common on commercial plans and some residential ones.
Fixed fees and net metering
- Fixed/connection charges — a flat monthly fee you'll keep paying even with solar, because you stay connected to the grid.
- Net metering terms — how the utility credits power you export. Full-retail credit is best; some utilities pay far less, which changes your ideal system size and whether to add a battery.
Put it together
| Pull this from your bill | Why it matters |
|---|---|
| Annual kWh | Sizes the system |
| Rate per kWh | Estimates savings |
| Rate structure (tiered/TOU) | Timing and battery value |
| Fixed fees | The bill you'll still pay |
From bill to real system
Your bill gives you a solid target, but it's still a plan. The actual system needs proper engineering, and a licensed electrician or PE must design and connect any grid-tied install. Read your bill, learn the terms here in the reference, and you'll walk into any solar conversation prepared.
FAQ
What number on my electric bill matters for solar?
Your kilowatt-hours (kWh) used — ideally the annual total or twelve months added up. That usage figure is what sizes a solar system, more than the dollar amount you pay.
What is a demand charge?
A fee based on your highest short burst of power use (kW), not total energy. It's common on commercial bills and some residential plans, and solar alone may not reduce it much.
How do I find my rate per kWh?
Divide the energy portion of your bill by the kWh used that month, or read the per-kWh rate listed on the statement. Rates often vary by season or time of day.
Related: For homeowners & DIY
Educational reference, reviewed 2026-07. A design aid, not a substitute for a licensed electrician or PE. Confirm the enforced NEC edition and local amendments with your AHJ.
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