What a Production Guarantee Is
A production guarantee is a promise from your installer that your system will generate at least a stated amount of electricity — usually measured in kilowatt-hours (kWh) — over a defined period, most commonly a year. It is the installer's way of standing behind their system design: they sized the array for your roof and usage, and they are willing to put a number on what it should produce.
Not every installer offers one, and the terms vary widely. The guarantee lives in your contract, so it is only as strong as the words on the page. Anything a salesperson tells you verbally that is not in the agreement does not count.
Bright Solar's terms: production guarantee terms for Bright Solar installations [TBD] — we are confirming the details and will publish them here. In the meantime, this page explains the concept so you can evaluate any installer's offer, including ours.
How a True-up Works
Most guarantees include a "true-up": at the end of the guarantee period, the installer's records (from your system's monitoring data) are compared against the promised output.
- If production meets or exceeds the promise, nothing happens. Overproduction usually earns you nothing extra — the guarantee is a floor, not a bonus.
- If production falls short, the installer compensates you for the missing kilowatt-hours, typically as a check or bill credit at a rate defined in the contract.
The guarantee is usually weather-adjusted: the promised figure assumes a typical year of sunshine for your area, so an unusually cloudy year may be accounted for in the calculation. What counts as an exclusion — storm damage, new shading from a neighbor's tree, or changes you made to the system — should be spelled out in the agreement.
Questions to Ask Any Installer
Whether you are talking to us or a competitor, these questions separate a real guarantee from marketing language:
- What exact kWh figure is guaranteed, and over what period?
- Is the guarantee adjusted for weather, and how?
- What is excluded — storm damage, shading changes, utility outages, my own changes to the system?
- If there is a shortfall, how and when am I compensated, and at what rate per kWh?
- How do I file a claim, and who do I contact?
- Does the guarantee transfer to a new homeowner if I sell the house?
- How long does the guarantee last, and what happens when it ends?
How It Differs from Equipment Warranties
A production guarantee and an equipment warranty cover different things, and it is easy to confuse them:
- Production guarantee (from the installer): covers output — how much electricity the system makes.
- Equipment warranties (from manufacturers): cover defects — if a panel or inverter fails prematurely, the manufacturer repairs or replaces it under warranty terms.
- Workmanship warranty (from the installer): covers installation quality — roof penetrations, wiring, mounting — for a set number of years.
A system can honor its equipment warranties and still underproduce because of a poor design or heavy new shading — that is exactly the gap a production guarantee is meant to cover. Ask for all three in writing: production guarantee, equipment warranties, and workmanship warranty.
Frequently Asked Questions
No. A panel warranty (from the manufacturer) covers defects and premature failure of the equipment itself. A production guarantee (from the installer) covers how much electricity the whole system produces. They are separate promises from separate parties, and you should have both in writing.
Under a typical guarantee, the installer compares your actual monitored output to the promised figure at the end of the guarantee period (the true-up). For a shortfall, you are compensated for the missing kilowatt-hours at the rate stated in your contract — often as a check or account credit.
Usually not. Storm damage, a neighbor's new tree, or changes you make to the system are commonly listed as exclusions, since they are outside the installer's control. Read the exclusions section of the contract carefully — it defines what the guarantee really promises.
Terms vary by installer — some guarantee annual output for a set number of years, others for longer periods. There is no industry standard length, so compare the duration as well as the kWh figure. Bright Solar's specific guarantee terms [TBD] — we will publish them here once confirmed.