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Solar Production Guarantees: What a Guarantee Should Actually Say
Learn how to read a solar production guarantee, including modeled kWh, weather and shade assumptions, exclusions, measurement, and remedies.
Quick answer
A useful production guarantee identifies annual kWh, the modeling method, allowed losses, measurement source, exclusions, period, and remedy. A broad savings promise is not the same thing.
Production and savings are different
Production is measured energy generated. Savings depend on how that energy is used, utility tariffs, exports, fixed charges, and financing, so a production term should not be presented as a guaranteed bill outcome.
Ask for the model inputs
A proposal should state system size, roof orientation, shade assumption, panel and inverter equipment, and modeled annual kWh. Without inputs, a headline number is hard to evaluate.
Read exclusions and measurement
Weather, outages, homeowner changes, equipment access, monitoring availability, and maintenance can affect a claim. Identify who measures performance and what data counts.
Understand the remedy
If output misses a threshold, the agreement should state whether the remedy is a payment, repair, additional equipment, or something else—and any required notice deadline.
Research and review
Reviewed for plain-language accuracy, source links, and consistency with SolarSavings calculator assumptions.
Reviewed by SolarSavings.energy Research Desk
Last reviewed August 14, 2026
This is educational content, not tax, legal, engineering, or financial advice. Confirm current incentives, tariffs, and contract terms with the relevant provider or qualified professional.
Frequently asked questions
Does a production guarantee guarantee savings?
No. Savings depend on utility rates, consumption, exports, and financing in addition to production.
Can weather void a guarantee?
Review the written exclusions and measurement terms; they vary by agreement.
What is annual kWh?
It is the amount of electricity expected or measured over a year, expressed in kilowatt-hours.
Primary sources
This guide was written for homeowners and reviewed against the following government and research resources. Programs and utility rules can change, so verify current details before making a financial decision.