Path-Q Solar
How should I compare solar quotes that use different production estimates?
Answer
Normalize the quotes by comparing predicted annual energy production in the same units, using the same site assumptions and system boundary. Do not compare system size or price alone; compare expected output, price per expected unit of energy, and the assumptions behind each estimate.
Key points
- Request annual production in the same unit, such as kilowatt-hours per year.
- Compare system capacity, roof layout, shading assumptions, orientation, tilt, losses, and degradation assumptions.
- Check whether estimates include all system components and whether one quote uses a more conservative scenario.
- Compare total installed price divided by predicted first-year production as one screening metric.
What it depends on
- The modeling method and weather data used
- Roof orientation, tilt, shading, and obstructions
- Equipment configuration and assumed losses
- Whether battery output or other loads are included in the estimate
Risks and trade-offs
- A higher production estimate may reflect optimistic assumptions rather than a better system.
- A low price per predicted kilowatt-hour is misleading if the estimate omits losses or uses an inconsistent system boundary.
- Production estimates are forecasts, not guarantees, unless the contract provides defined remedies.
Information you may need
- Annual and monthly production estimates for each quote
- System size, equipment list, layout, and shading report
- Modeling assumptions and expected degradation
- Any production guarantee and its measurement method
Your next step
What to do next
Ask each installer for a standardized production worksheet and compare the quotes using identical assumptions.
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