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Will it pay off where you live?

Enter four things. We'll combine NREL irradiance, your utility's published rate, and our field-measured derate to give you a real number — with a confidence band, because anyone selling you a single number is selling you something.

Your situation

All inputs stay in your browser.

Zip code Avg monthly bill ($)

Kit size

Most state laws cap at 1,200 W.

Sun exposure

Daytime occupancy

How much of the panel's output you'll absorb.

Climate region

Utility rate ($/kWh)

Check your last bill — divide total cost by total kWh used.

Year-one savings · Estimated

$0± $0

Payback period

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Year-one kWh

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20-year value

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Based on your inputs

Three kits worth comparing.

All reviews →

Best 800W

EcoFlow STREAM Microinverter

$599 · UL 3700 · 2 panel inputs

Best with battery

EcoFlow STREAM Ultra

$2,399 · 1.92 kWh built-in

Budget pick

Bright Saver 400W Starter

$389 · Single panel · One outlet

Method: kWh/yr = kit_W × climate_sun_hrs × 365 × derate(0.78) × sun_factor. Savings = kWh × occupancy × rate. Cost assumed at $0.65/W. 20-yr value uses 3% annual rate escalation, 0.5%/yr panel degradation. Confidence band ± 16%.