Most of the buying decision in a solar quote hides behind two lines: the equipment list and the warranty section. Both are usually short, and both are usually the place where a salesperson expects you not to linger. This page gives you a small set of questions you can ask about each, with the reasoning behind them. Every product-specific warranty term stays unknown until you hold the manufacturer's document.
If you want the arithmetic side of the same quote — cash price, loan principal, fees — start with reading a solar quote line by line. This page is about the hardware.
Start with model names, not brand names
Ask the salesperson to write the exact panel model and the exact inverter model into the proposal. Brand names alone are not enough: a maker can sell several lines with different performance and different warranty terms under one logo. A model number is the string you can look up later.
The Department of Energy's description of a federally funded solar marketplace breaks shopping for a rooftop photovoltaic system into three parts: what quality of equipment to buy, how to finance it, and which contractor installs it. Equipment sits first in that list, which is a useful reminder that financing and installation are separate questions, not substitutes for it. The same account describes how a national laboratory helped that marketplace build a model-level comparison guide for panels, batteries and inverters — meaning model-level detail is the level at which equipment can actually be compared.
On the quote itself, ask for:
- Panel manufacturer, model number, wattage, and quantity.
- Inverter (or microinverter) manufacturer and model number.
- Racking manufacturer and model, if it is listed separately.
- Whether any battery is included, and its model.
The one equipment number DOE does state
DOE's guide for homebuilders says that commercially available residential panels use crystalline silicon cells, and that modules are expected to last 25 years or more while still producing more than 80 percent of their original power.
Read that carefully. It is an expectation about crystalline silicon modules in general. It is not a manufacturer's warranty, not a performance guarantee for the panels in your quote, and not a commitment about what happens in year 26. If a salesperson quotes a 25-year figure as if it were a warranty obligation, ask to see the document that actually binds the maker — the warranty text, not the brochure.
Warranty questions: three documents, not one
"Warranty" on a solar quote can mean at least three different promises from at least three different parties. Ask for each in writing:
1. Equipment warranty
This comes from the manufacturer of the panel or inverter. What you want to know: what is covered, for how many years, what the maker will do (replace, repair, refund), and whether the payment covers labor to remove and reinstall the hardware. Do not assume the manufacturer pays labor. Ask for the manufacturer's own warranty document, and check whether it is transferable if you sell the house.
2. Workmanship or installation warranty
This comes from the installer, and it covers the quality of the installation rather than the products. Ask how long it runs, what it covers (for example, leaks at the mounting points or wiring faults), and what happens to that promise if the installer goes out of business or is acquired. The DOE guide notes that installers handle the utility interconnection agreement for the homeowner, which tells you the installer's role continues past the physical install — worth knowing when you weigh how long their promises should last.
3. Roof warranty
Your roofing or homeowner's coverage is a separate matter, and solar installation involves penetrating the roof where panels are mounted. Ask the salesperson how penetrations are sealed and what your existing roof coverage says about work done on the roof. This page cannot tell you what your roof policy covers; that comes from your insurer and your roofer's documents.
Questions worth putting on the table
- What is the exact model number of each panel and inverter?
- Can I have the full manufacturer warranty document for each, before I sign?
- Does the manufacturer's warranty pay labor to remove and reinstall failed equipment?
- Is the equipment warranty transferable if I sell the home, and does that require registration?
- How long is your installation warranty, and who honors it if your company is sold or closes?
- What does my existing roof coverage say about penetrations and mounted hardware?
- If a panel fails or underperforms, what is the process, and who pays for the visit?
If the salesperson cannot give you model numbers or a warranty document, that is itself information. The CFPB's advisory for solar shoppers recommends comparing proposals from multiple installers and lenders and asking for a written breakdown of the work, the materials and the cost of each one. Model numbers and warranty documents are part of that written breakdown.
What this site cannot confirm
We cannot tell you how long a specific panel will last, what a specific warranty says, or whether a particular product is right for your roof. Warranty terms vary by manufacturer and by product line, and they change. The DOE module-life statement is general guidance; it is not a product specification for the panels in any quote you enter.
Equally, a model number on a spec sheet does not tell you whether your roof is suitable, whether your electric panel can take the system, or whether your utility will approve the connection. DOE notes that power from a solar system is wired into the home's main electric panel, that special requirements apply to labeling, panel sizing and breaker placement, and that an interconnection agreement with the local utility is needed before activation. The nature of those agreements varies by utility and local authority. Those are site-specific questions for a qualified professional and your utility, not something a comparison page can settle.
A clearly hypothetical example
The following is made up to show the process, not a real quote and not a real warranty.
Suppose a quote lists "24 x Brand X 400 W panels" and "Brand Y inverter," with a note saying "25-year warranty." The shopper asks for model numbers and receives two manufacturer documents. The panel document covers product defects for 12 years and a separate output promise for 25 years; the inverter document covers 10 years. The installer's own workmanship warranty in the contract is 5 years. Nothing in those documents promises to pay labor for a panel removed and reinstalled under the manufacturer warranty.
Now the shopper knows something concrete: those are three different promises with three different lengths, held by at least two different parties, and the quoted "25-year" line covers one of them. Whether any of those terms is acceptable is a judgment call, but it can only be made with the documents in hand.
What to do next
Before you compare dollars, collect the documents. Write the exact panel, inverter and battery model numbers from each quote into your own notes, together with a short reminder of what each warranty covers and for how long. Then, when you enter the quotes in the comparison tool, you are comparing the same kind of number — and you will know which questions the salespeople could actually answer. At the end of the comparison, check what the numbers do and do not include on the assumptions page.
