Five questions before you sign anything

A residential solar contract is a 25-year decision wrapped in a 30-page document. Most homeowners sign it after a single in-person sales conversation. Here are the five things you need to verify before you put your name on anything — small enough to remember, specific enough to stop the bad outcomes.

By The Solar Brief Editorial Team  ·  Reviewed by To be assigned (paid solar advisor)  ·  Updated May 2026 (post-OBBBA refresh)

1. The specific equipment make and model — written into the contract

Not "tier-1 monocrystalline panels." Not "premium 400W high-efficiency modules." The actual brand and model number. Q Cells Q.PEAK DUO ML-G11. REC Alpha Pure 410W. Panasonic EverVolt EVPV410H. SunPower Maxeon 6 425W.

Same goes for the inverter (Enphase IQ8M, SolarEdge SE7600H-US, Tesla Solar Inverter) and the battery if you're including one (Tesla Powerwall 3, Enphase IQ Battery 5P, FranklinWH aPower).

If the contract reads "tier-1 panels and string inverter," the installer reserves the right to substitute whatever they have in the warehouse on install day. That's a real outcome, not a theoretical one. Specificity is consumer protection.

2. Modeled annual production in kWh — with the model output attached

Every reputable installer designs the system in software (Aurora Solar, Helioscope, PVsyst, OpenSolar). The software produces an annual production estimate in kilowatt-hours per year that accounts for your roof's pitch, orientation, shading, and local irradiance. That number — not the system's nameplate kW capacity — is what determines your savings.

Ask for the production model output, either as a PDF or a screenshot. The good installers share it; the worried ones tell you "we use industry-standard assumptions." Do not accept a verbal "should produce about 12,000 kWh" without the underlying model behind it.

If two installers quote you the same 8 kW system with annual production estimates 1,500 kWh apart, the higher number is probably wishful. Ask both of them how they modeled shading.

3. Workmanship warranty length — with the issuing entity named

Three warranties matter on a solar install, and they cover different things:

• Panel warranty (usually 25 years, from the panel manufacturer): covers panel defects, output degradation beyond spec.
• Inverter warranty (typically 12 years, from the inverter manufacturer): covers inverter failure.
• Workmanship warranty (varies wildly, from the installer): covers everything else — roof penetrations, mounting hardware, wiring, labor.

The workmanship warranty is the one most likely to come due in years 5–15, and it's the one most likely to be quietly short. We see installers in our partner network offering anywhere from 2 to 25 years. Ten years is a reasonable floor for a serious purchase.

Ask: "Is the workmanship warranty issued by the company doing the install, or by a third party?" Some installers white-label their warranty through a marketing partner that may or may not exist in 2036. You want the warranty issued by an entity with skin in the game.

4. Itemized state incentives — and (for lease/PPA) the §48E passthrough question

Important 2026 update: the federal residential Investment Tax Credit (§25D) ended December 31, 2025. Cash and loan buyers in 2026 do not receive a federal credit on the system. The §48E commercial credit, which lease and PPA providers capture, remains available through 2027 — but it goes to the installer, not to you, with some installers passing value through as lower per-kWh rates and some not.

For cash and loan quotes: itemize state credits (SuSI in NJ, SMART in MA, AZ Residential Solar Tax Credit, SGIP in CA), local utility rebates, and any other incentives line-by-line. State incentives now do most of the math on payback, so a quote that bundles them into a single "after-incentives" number is hiding which lever is doing the work. Ask for the itemized version.

For lease and PPA quotes: ask explicitly, "How much of the §48E credit are you passing through to my per-kWh rate, and can you show me the math?" Reputable installers walk through specific numbers. Vague answers ("our pricing reflects current incentives," "proprietary pricing model") are signals the installer is pocketing the §48E credit. Get three lease quotes in 2026 — variance between TPO providers is meaningful.

5. Cancellation clause — verify the window matches your state's law

Federal law and most state consumer-protection statutes guarantee a 3-day cancellation right after signing a residential solar contract. Some states extend this to 5 or 7 days for door-to-door sales. The contract should explicitly name your cancellation window in business days, and the language should match what your state's attorney general office publishes.

Look also for what you owe if you cancel after the cancellation window — typically permitting fees and design work the installer has already completed, which is reasonable. Some contracts include a "liquidated damages" clause demanding 10–20% of the total contract value if you cancel any time before install. That's not standard. Negotiate it out, or walk.

A quick note on bonus things to verify

Beyond the five must-haves, three more checks save real money and friction over the system's life:

Roof warranty handling. If your roof has an existing manufacturer warranty, ask how the installer protects it. Drilling penetrations into a warrantied roof can void the warranty unless the installer is on the roofer's approved list, uses an approved racking system, or installs to a documented spec. The wrong answer here costs you in year 8 when you have a leak and the roofing company says "those panel installers voided your warranty."

Permitting and interconnection timeline. Solar projects sit in utility interconnection queues for 6 to 16 weeks in most US markets. Ask the installer for a written estimate of permit submission date, expected interconnection date, and what happens if the utility queue is longer than estimated. "We'll let you know" is not a written estimate.

Production monitoring access. Modern systems include monitoring software (Enphase Enlighten, SolarEdge mySolarEdge, Tesla app). You should have full access — not "limited installer access" — so you can see production data day one. Ask for a demo of the monitoring app before you sign.

The honest summary

A reputable installer will give you all five concrete answers without flinching. They'll write the equipment make and model into the contract, share the production model output, name the workmanship warranty entity, itemize incentives correctly, and confirm the cancellation window. The conversation takes 20 minutes. If the answers come back vague or pivot to financing options, the rest of the relationship will too. Walk politely, and get another quote.