The quick answer
The most useful questions to ask before going solar come down to four things: is my roof and electrical panel actually a good fit, what will the system cost and pay back now that the 30% federal tax credit ended on December 31, 2025, how will my utility credit the power I send back to the grid, and is the company installing it licensed, insured, and accountable for its work. Get honest answers to those four and the rest of the decision gets a lot easier.
Updated for 2026. Reviewed by the MySolarFY editorial team.
A quick note on what this checklist is and is not. This is a neutral, homeowner-first decision guide, part of our solar basics series: the questions to ask yourself about your home, the questions to ask about the money, and the questions to ask a company before you sign. It does not rank or recommend any installer. For the full dollars-and-cents payback math, see our companion analysis on whether solar panels are worth it.
Before you sign: the questions that change the outcome
- Your roof needs enough life left in it. Panels last about 25 to 30 years and lose roughly 0.5% to 1% of output per year, so a roof near the end of its life should be replaced before, not after, install (U.S. Department of Energy, as of 2024).
- Ask if your electrical panel has room. Under the NEC 120% rule (Article 705.12), a standard 200-amp panel often limits rooftop solar to about a 40-amp backfeed breaker, so an older or fully loaded panel may need an upgrade (DOE Solar Permitting Guidebook, as of 2026).
- The federal homeowner credit is gone. The 30% federal Residential Clean Energy Credit (Section 25D) ended for systems placed in service after December 31, 2025 (IRS, as of 2026), so a 2026 cash or loan buyer cannot claim it. Ask which state, local, and utility incentives still apply.
- Ask how your utility credits exported power. Net metering can credit the power you export at or near the full retail rate, but the rules vary by state and utility, so confirm your local policy before you size a system (DOE Homeowner’s Guide to Solar, as of 2026).
- Screen the company, not the pitch. Ask for licensing, NABCEP certification, and all three warranties: product, performance, and workmanship (the last often 1 to 10+ years) (EnergySage solar warranties guide, as of 2025).
The rest of this page is the full checklist behind those five, grouped the way the decision actually happens: is my home a fit, does the money work, and can I trust this company. It is built to be printed and taken to a sales appointment.
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Why ask questions at all? Because the price of doing nothing is real
Before the checklist, it helps to see what solar is actually competing against: your future utility bills. A typical U.S. home uses about 10,800 kWh a year, and the average residential electricity price is about 18.83 cents per kWh (EIA, as of March 2026). That is roughly $2,030 a year today, and utility rates have generally climbed over time. The table below is our own estimate of what that same home hands the utility over 25 years at three different rate-increase assumptions. It is an illustration, not a quote, but it frames why the questions below are worth getting right.
| If your electricity price rises by… | Est. 25-year total paid to the utility |
|---|---|
| 0% per year (flat, unrealistic) | about $50,800 |
| 2% per year | about $65,100 |
| 4% per year | about $84,700 |
Our estimate. Inputs: 10,800 kWh per year at 18.83 cents per kWh (EIA, as of March 2026), compounded over 25 years at the stated annual increase. Your usage, rate, and rate increases will differ; this is a national illustration, not a prediction. The job of a solar system is to offset a large share of that spend, which is exactly why the fit, cost, and net-metering questions below matter.
A rough sense of the other side: a system built to cover about 90% of that same 10,800 kWh home would offset roughly 9,700 kWh a year, worth about $1,830 at today’s 18.83 cents per kWh (our estimate; actual production depends on your roof, shading, and location). The questions below are how you find out whether your roof can get there.
Part 1: Confirm your home is a good fit for solar
The fastest way to waste a solar consultation is to skip the fit questions and jump to price. A system on the wrong roof, in heavy shade, or behind an undersized electrical panel will underperform no matter how good the price looked. Ask these before anything else.
Your roof needs enough life left before you install
If your roof has fewer years left than the solar system, replace or repair it before you install. Solar panels last about 25 to 30 years, so putting them on a roof with 5 to 10 years left means paying to remove and reinstall the array later, often several thousand dollars (U.S. Department of Energy, as of 2024). A good answer from an installer includes a look at your roof’s age and condition and a recommendation to fix it first if needed, not a shrug. Panels themselves degrade slowly, about 0.5% to 1% per year, and typically still produce 80% to 90% of their original output at year 25 (EnergySage, as of 2025).
Shade and orientation decide how much you produce
Shade is the quiet killer of solar production, so ask for a shading analysis, not a guess. Trees, chimneys, dormers, and neighboring buildings all cut output, and a south-facing roof plane generally produces the most in the U.S. (DOE Homeowner’s Guide to Solar, as of 2026). A credible installer will show you a modeled production estimate for your specific roof, in kilowatt-hours per year, and be honest if a shaded roof means fewer, higher-efficiency panels or a smaller system. You can sanity-check any estimate yourself for free with NREL’s PVWatts calculator.
What the 120%, 20%, and 33% panel rules really mean
Ask whether your main electrical panel can accept solar without an upgrade, because this is where the “rules” you have read about actually apply. The one that matters is the NEC 120% rule (Article 705.12): for a typical breaker connection, 125% of the solar inverter’s output current plus the rating of the breaker protecting your panel’s busbar cannot exceed 120% of that busbar’s rating (DOE Solar Permitting Guidebook, as of 2026). In plain terms, on a common 200-amp panel with a 200-amp main breaker, that math usually limits the solar backfeed breaker to about 40 amps, which is the so-called “20% rule” (40 is 20% of 200). If your system needs more than the panel allows, you may need a main-panel upgrade or a line-side connection, both of which add cost, so it is a fair question to raise early.
Note: The “33% rule” that shows up in search results is not National Electrical Code text. There is no general NEC rule capping solar at 33% of your service. Utilities and your local permitting office (the AHJ) set their own distributed-generation size limits, so the honest answer is that any percentage cap on system size must be checked against your specific utility and city, not assumed from a blog (NFPA, as of 2024). An installer who cannot explain your panel’s specific limit is a red flag.
Size the system to your real usage, plus what will change it
Size the system to your real usage, and tell the installer about anything that will raise it. A system built for last year’s bills will fall short if you add an EV, a heat pump, or central air, and it will oversize (and overspend) if you are about to cut usage. A good design starts from 12 months of your actual utility bills, not a rule of thumb. For the bigger picture on how a home system produces and offsets your usage, see how solar works for homeowners.
| Home-fit question | Why it matters | What a good answer sounds like |
|---|---|---|
| How old is my roof? | Panels outlive a worn roof; reinstalling later is costly | “Let’s check the roof age and condition first; replace it now if it is near end of life” |
| How much shade do I get? | Shade cuts production more than people expect | “Here is a modeled kWh estimate for your specific roof and shading” |
| Can my electrical panel handle it? | The NEC 120% rule can force a panel upgrade | “Your panel is X amps; here is the specific limit and whether an upgrade is needed” |
| What is my real annual usage? | The system should match your kWh, plus planned additions | “We sized this from your last 12 months of bills, plus your planned EV” |
Part 2: Confirm the money actually works
Once your home is a fit, the money questions decide whether solar is a good investment or an expensive mistake. Ask for real numbers in kilowatt-hours and dollars, not just a monthly payment.
What still pays for solar in 2026
No. The 30% federal Residential Clean Energy Credit (Section 25D) ended for systems placed in service after December 31, 2025 (IRS; IRS One Big Beautiful Bill FAQ, as of 2026). A homeowner who buys solar in 2026 with cash or a loan cannot claim it. You will still see installer pages and old articles implying the 30% credit is available; for 2026 buyers that is out of date. A separate commercial credit, Section 48E, can apply to leased or PPA systems, but the business that owns the panels claims it, not you. So the sharper money question now is which state, local, and utility incentives you qualify for, since those are what remain. For the full picture, read what the end of the federal solar tax credit means.
The total cost and your estimated payback
Ask for the itemized, all-in cost before and after any incentives, plus a payback estimate in years. A trustworthy quote shows system size in kilowatts, the equipment brands and models, the gross price, every incentive applied, and the net cost, so you can compare quotes on the same basis. Costs vary widely by system size and region; our guide on how much solar panels cost breaks down the typical ranges. Be wary of a quote that leads with only a monthly payment and hides the system price, and remember that solar panels are not free even under a no-money-down plan.
How your utility credits the power you send back
Net metering is the mechanism that turns extra midday production into bill savings, so ask exactly how your utility handles it. Under full net metering, exported power is credited at or near the retail rate and rolls forward month to month; other utilities use lower export rates or time-of-use pricing that changes the math (DOE Homeowner’s Guide to Solar, as of 2026). Because this is set by your state and utility, it is one of the most location-specific answers on this whole list. Learn the mechanics in our explainer on how net metering credits your solar exports.
Note: How much this question matters depends entirely on where you live. Some states still credit exported power at close to the full retail rate, while others credit exports at much lower rates tied to the utility’s avoided cost. California’s current net-billing tariff is the most-discussed example of the low-export-rate approach, which is why homeowners there increasingly pair solar with a battery. That one difference can swing a payback by years, so confirm your own utility’s export rate before you size a system (DOE Homeowner’s Guide to Solar, as of 2026).
Cash, loan, lease, or PPA: who keeps the incentives
How you pay decides who owns the system and who keeps any incentives, so match the option to your goal. If you want the most lifetime savings and to keep state and local incentives, ownership (cash or loan) is the path. If you want no up-front cost and a simpler bill, a lease or PPA can work where you are eligible, but the company that owns the panels keeps the incentives, and it is a long-term agreement, not free power.
| How you pay | Up-front cost | Who owns the system and keeps incentives | Best when |
|---|---|---|---|
| Cash | Full system price | You | You want the fastest payback and most lifetime savings |
| Solar loan | Little to none, financed | You | You want ownership without paying cash up front |
| Lease or PPA | $0-up-front where eligible | The third-party owner, not you | You prefer no up-front cost and a fixed, simpler bill |
Ownership and incentive treatment summarized from EnergySage and the DOE Homeowner’s Guide to Solar (as of 2026). “No up-front cost” refers to qualifying lease or PPA financing where eligible; it is not free solar. To weigh the long-run numbers, use our solar financial analysis.
Why your electric bill might still be high
Ask this before you sign, because a “zero bill” promise is rarely the full story. Even a well-designed system leaves a bill in common cases: the system was sized to offset only part of your usage, your usage rose (EV, heat pump), your utility charges fixed monthly or minimum fees that solar cannot erase, or time-of-use rates mean your evening power still costs money (DOE Homeowner’s Guide to Solar, as of 2026). A good installer explains what your remaining bill will realistically look like, rather than promising it disappears.
Part 3: Vet the company before you sign
This is where “questions to ask a solar installer” earns its keep, and where we stay strictly neutral: we do not rank or recommend companies. Instead, here is how to vet any installer on objective criteria, the same way a licensed trade or the American Solar Energy Society recommends (ASES, Questions to Ask an Installer, as of 2026). Ask every company the same questions and compare the answers.
Licensing, insurance, and certification
Confirm the company holds the right state license, carries insurance, and employs or contracts NABCEP-certified installers. NABCEP is the industry’s recognized professional certification for PV installers, and a licensed electrician should be involved in the work (ASES, as of 2026). A good answer names the license, confirms insurance, and says whether the crew is in-house or subcontracted, since in-house crews are generally more accountable.
The three warranties, all in writing
Get all three warranties in writing, because they cover different failures. The product (equipment) warranty covers panel and hardware defects, often 10 to 25+ years; the performance warranty guarantees a minimum output, commonly around 90% at year 10 and 80% at year 25; and the workmanship (labor) warranty from the installer covers installation issues like roof leaks, often 1 to 10+ years (EnergySage, as of 2025). A strong answer hands you the actual warranty documents, not verbal assurances.
Equipment specifics and who handles the permits
Ask for the specific panel and inverter brand, model, and wattage, plus who manages permitting and utility interconnection. Vague contracts that say “or equivalent” leave room for cheaper substitutions. A good installer names the equipment, provides a production estimate in kilowatt-hours, and confirms they handle the permits, inspections, and interconnection paperwork with your utility (ASES, as of 2026).
References and the fine print
Ask for recent local references and read every line of the contract, especially on a lease or PPA. Check for an escalator clause (a payment that rises each year), the total of payments over the term, transfer terms if you sell the home, and who is responsible for monitoring and repairs. A reputable company welcomes references and gives you time to read the contract rather than pressuring a same-day signature.
| Vetting question | Why it matters | Red flag answer |
|---|---|---|
| Are you licensed, insured, NABCEP-certified? | Basic competence and accountability | Dodging the license question or “we don’t need one” |
| Can I see all three warranties in writing? | Different warranties cover different failures | Verbal promises, no documents |
| Exactly which panels and inverters? | Prevents cheaper substitutions | “Tier-1” with no brand or model |
| Who handles permits and interconnection? | Avoids you being stuck with paperwork | “That’s on you” |
| Can I see references and the full contract? | Reveals escalators and hidden terms | Same-day signing pressure |
MySolarFY is a free matching service, not an installer. We help you get quotes from licensed installers that serve your area so you can ask these questions and compare real answers side by side. Learn how MySolarFY works and the data and sources behind our guides.
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Frequently asked questions
What are the most important questions to ask before going solar?
Start with fit, money, and trust. On fit: is my roof young enough (panels last 25 to 30 years), how much shade do I get, and can my electrical panel handle solar under the NEC 120% rule (DOE, as of 2026). On money: what is the itemized cost and payback, how does my utility credit exported power, and which incentives still apply now that the federal credit ended on December 31, 2025. On trust: is the company licensed, insured, and NABCEP-certified, and are all three warranties in writing (ASES, as of 2026). Get clear answers to those and you can decide with confidence.
What happened to the 30% federal solar tax credit?
The 30% federal Residential Clean Energy Credit (Section 25D) ended for systems placed in service after December 31, 2025 (IRS, as of 2026), so a homeowner buying in 2026 with cash or a loan cannot claim it. A separate commercial credit, Section 48E, can apply to leased or PPA systems, but the business that owns the system claims it, not the homeowner. Ask instead about state, local, and utility incentives, which are what remain. See what the end of the federal solar tax credit means for the details.
What are the solar 120%, 20%, and 33% rules?
The 120% rule is real: it is NEC Article 705.12, and it means 125% of your solar inverter’s output current plus the rating of the breaker protecting your panel’s busbar cannot exceed 120% of that busbar’s rating (DOE Solar Permitting Guidebook, as of 2026). The “20% rule” is just that math on a common 200-amp panel, which usually caps the solar breaker near 40 amps. The “33% rule” is not National Electrical Code text; any cap on system size relative to your service is set by your utility and local permitting office, so check it locally (NFPA, as of 2024).
Why is my electric bill still high after going solar?
Usually one of five reasons: the system was sized to cover only part of your usage, your usage went up (an EV or heat pump), your utility charges fixed monthly or minimum fees solar cannot erase, time-of-use rates make evening power expensive, or the system is underperforming from shade or a fault (DOE Homeowner’s Guide to Solar, as of 2026). Ask your installer before signing what your realistic remaining bill will be, and confirm how your utility’s net metering credits your exports so you are not surprised.
What is the biggest downside of going solar?
The honest answer is the up-front commitment and that savings are not guaranteed. Owned systems have a real cost even with financing (solar panels are not free), payback takes years, and now that the federal residential credit ended on December 31, 2025, the economics lean more on your electricity rate, your production, and your state and utility incentives. Shade, an aging roof, or an undersized electrical panel can also add cost. That is exactly why the fit and money questions above matter before you commit.
What questions should I ask a solar installer before signing?
Ask the same objective questions of every company: are you licensed, insured, and NABCEP-certified; what are the product, performance, and workmanship warranties in writing; exactly which panel and inverter brands and models will you use; who handles the permits and utility interconnection; and can I see local references and the full contract (ASES; EnergySage, as of 2026). Watch for same-day signing pressure, verbal-only warranty promises, and quotes that hide the system price behind a monthly payment.
Do these questions change if I live in California, Texas, or another state?
The fit and vetting questions are the same everywhere, but the money answers are state and utility specific. Net metering, export rates, and the incentives that remain after the federal residential credit ended on December 31, 2025 vary by state and by utility, so your local net-metering policy and available rebates are the parts to confirm for your address (DOE Homeowner’s Guide to Solar, as of 2026). Start with how net metering works, then check what applies in your area.
Reviewed by the MySolarFY editorial team on July 2, 2026. Figures were verified against the linked IRS, U.S. Department of Energy, NREL/EnergySage, NFPA, and American Solar Energy Society sources as of July 2026. Net-metering rules, incentives, and electricity rates change and vary by state and utility, so confirm current terms for your address before you decide. MySolarFY does not provide tax or financial advice; consult a licensed professional about your own situation. Learn more about how MySolarFY works.
MySolarFY is a free service that matches homeowners with licensed solar installers. We are not an installer, financing company, tax advisor, or government program, and we do not rank or recommend individual installers. “No up-front cost” refers to qualifying lease or PPA financing, where eligible homeowners may have no out-of-pocket cost at installation. Lease and PPA terms typically run 20 to 25 years, may include an annual price escalator, and total payments may exceed the cost of a cash purchase; on a lease or PPA the incentives and tax benefits go to the company that owns the system, not the homeowner. The federal residential solar tax credit (Section 25D) ended for systems placed in service after December 31, 2025, so 2026 homeowner-buyers cannot claim it. Solar panels are not free and monthly payments apply. Eligibility, savings, incentives, and rates vary and are not guaranteed. See our full disclaimer.
