Most people arrive at a solar quote with questions about panel brands and efficiency ratings. Those matter less than the assumptions buried in the production estimate, because that estimate is what the entire financial case rests on.
A quote showing generous output with optimistic shading and degradation assumptions will look better than an honest one, and the difference does not appear until years later. Our note on whether you need an electrician covers who should be doing the work.
A Note on Getting Advice
This lists questions worth asking rather than advising on any purchase. Installers are selling equipment, which makes them the wrong source for tax and financial advice specifically. A tax advisor and, where relevant, an independent energy consultant answer different questions than a salesperson does.
Quick Answer
Ask how the production estimate was calculated, what happens if it falls short, who holds each warranty, and what the total cost is including permitting and interconnection.
Licensing and Credentials
Who holds the license
Ask for the license number and verify it with your state board rather than accepting a claim. Verification is public and takes minutes.
Who does the actual work
Many companies subcontract installation. Knowing whether the crew is employed or subcontracted tells you who is accountable if something goes wrong.
Insurance and bonding
Ask for proof rather than assurance. This protects you if there is damage during the work.
How long in business locally
Warranties are worth what the company backing them is worth, and solar has a history of installers closing. Our note on permits covers what a licensed installer handles.
The Production Estimate
This is the number that determines whether the investment works, and it is the one most worth interrogating.
Ask what software or method produced it, what shading analysis was done, and whether it accounts for your specific roof orientation and pitch rather than a regional average.
Ask what annual degradation rate was assumed, since panels produce slightly less each year and an optimistic assumption inflates the long-term case.
Then ask what happens if actual production falls materially short. Some installers offer a production guarantee, most do not, and knowing which you have matters. Our note on how shade affects panels covers the shading question.
Total Cost, Not Panel Cost
Ask for an itemized quote separating equipment, labor, permitting fees, interconnection costs, and any monitoring subscription.
Ask specifically what is excluded, since electrical panel upgrades, roof repairs, and tree removal are common additions discovered after signing.
Ask whether the quoted price is before or after incentives, because presenting a post-incentive figure as the price is a standard practice that makes comparison difficult.
And ask what triggers a change order, so you know under what circumstances the number moves after work begins.
Warranties, Plural
There are usually three and they are held by different parties, which is the thing people miss.
Panel warranties come from the manufacturer and typically cover product defects and a production floor over a long term.
Inverter warranties are usually shorter and come from a different manufacturer, and inverters are the component most likely to need replacing.
Workmanship warranty comes from the installer and covers the installation itself including roof penetrations. That is the one that disappears if the company does, which is why longevity matters. Our note on what a warranty covers covers the detail.
Equipment Questions Worth Asking
Equipment matters less than the assumptions in a quote, and a few questions about it are still worth asking.
Ask which inverter type is proposed and why. String inverters, microinverters, and power optimizers behave differently under partial shading, and the right answer depends on your roof rather than on which the installer prefers.
Ask whether the panel and inverter manufacturers are companies likely to exist in fifteen years, since a warranty from a company that folds is worth nothing.
Ask what happens if the specified equipment is unavailable at installation, and whether substitutions require your approval.
Ask about monitoring at the panel level versus the system level, since panel-level monitoring identifies a single failing panel where system-level monitoring only shows total output dropping.
None of these decide the purchase on their own, and the answers tell you whether the installer is thinking about your roof or reading from a script. Our roundup of monitoring and production meters covers that side.
Ownership Structure
Ask directly whether the proposal is a purchase, a loan, a lease, or a power purchase agreement, since the presentation can obscure which.
A lease or power purchase agreement means the company owns the equipment on your roof, which affects resale and means you are not the one holding the asset.
With financing, ask about the interest rate, the term, whether there is a dealer fee built into the cash price, and whether the loan is secured against the property.
These are the questions where an installer’s interest and yours diverge most, which is a reason to have the answers in writing. Our note on choose solar panels covers why ownership matters at sale.
Roof and Structure
Ask what the assessment found about roof condition and remaining life, and what the installer recommends if it is aging.
Ask whether a structural assessment was done and whether the roof can carry the array plus wind and snow loading for your area.
Ask how penetrations are flashed and sealed, and what the workmanship warranty covers if a leak appears.
Installing over a roof needing replacement within a few years creates a substantial future cost, and an installer who does not raise this unprompted is worth noting.
After Installation
Ask who handles the utility interconnection application and permission to operate, and roughly how long that takes locally.
Ask what monitoring is included, whether it carries an ongoing fee, and whether you retain access if the installer ceases trading.
Ask what maintenance is expected, who to call for a fault, and what the response commitment is.
And ask what documentation you receive at handover, since permits, inspection records, and warranty paperwork are what a future buyer will want. Our note on whether panels need servicing covers ongoing upkeep.
References Worth Chasing
Asking for references is standard and most people never follow up, which wastes the one check that reveals how a company behaves after payment.
Ask for customers from two or three years ago rather than recent ones, since a recent installation says nothing about warranty service or how faults get handled.
Ask those customers whether production matched the estimate, which is the question the installer cannot answer for you.
Ask whether anything went wrong and how the company responded, since every installer has problems and the useful information is what happened next.
Local review platforms and your state licensing board both hold complaint records, and those are worth checking alongside the references a company chooses to give you.
Warning Signs
Pressure to sign today, or an offer that expires within hours, is a sales technique rather than a genuine deadline.
Reluctance to provide an itemized quote, a license number, or references makes comparison impossible, which is frequently the point.
Production estimates substantially higher than competing quotes for the same roof suggest optimistic assumptions rather than better equipment.
And any claim that solar will eliminate your bill entirely deserves scrutiny, since fixed charges and connection fees generally remain regardless of generation.
Questions for an Installer FAQ
What is the most important question?
How the production estimate was calculated and what happens if actual output falls materially short. That estimate underpins the entire financial case.
How do I verify a license?
Through your state licensing board rather than by asking the company. Verification is public, free, and takes a few minutes.
How many quotes should I get?
Enough to compare assumptions rather than just prices. Production estimates varying widely for the same roof tells you something about whose numbers to trust.
What is usually excluded from a quote?
Electrical panel upgrades, roof repairs, tree removal, and sometimes permitting fees. Asking what triggers a change order surfaces most of it.
Which warranty matters most?
The workmanship warranty, because it covers the installation including roof penetrations and it depends entirely on the installer still existing.
Should I ask about tax credits?
Ask what incentives apply, and treat tax questions as a matter for a tax advisor. Installers sell equipment and are not the right source for advice on your return.
What should I get in writing?
Everything: itemized cost, production estimate and its assumptions, all three warranties, ownership structure, and the timeline through permission to operate.
What are the warning signs?
Pressure to sign immediately, refusal to itemize, unverifiable credentials, production estimates well above competing quotes, and claims that your bill will disappear entirely.
