A red flag is a reason to verify, not proof that a proposal is bad
Solar proposals combine engineering assumptions, utility rules, equipment, construction scope and financing. A number that looks unusual can have a legitimate explanation, but the explanation should be clear enough that a homeowner can verify it before signing.
Use the checks below to identify questions that deserve a written answer. Home Solar Atlas does not use these signals to rank installers or automatically choose a proposal.
1. Panel count and module wattage do not reconcile with quoted DC system size
For a simple array, module count multiplied by module nameplate watts should reconcile with the quoted DC system size after converting watts to kilowatts. A proposal with two module groups can still reconcile when each group is calculated separately and the results are added.
A mismatch can come from a proposal revision, a copied system size, mixed module groups or a number that is not actually the array DC nameplate. Verify the exact module quantities and wattages before using system size in price-per-watt or production comparisons.
2. A large production forecast is shown without the modeling assumptions
Annual production depends on more than installed kW. Roof orientation, tilt, shading, system losses, weather data, inverter behavior and multiple roof planes can materially change a first-year forecast.
Treat a high kWh number as a claim to review, not as evidence that one proposal is automatically better. Ask for the production-model report and compare the proposal with an independent planning reference using the same DC system size and representative roof geometry.
3. A 100% or 110% solar offset is shown without the annual household kWh baseline
Solar offset is an annual energy ratio: first-year solar production divided by annual household electricity use. It is not the same thing as percentage bill savings.
A proposal should make the usage baseline behind the offset claim clear. Fixed utility charges, time-of-use pricing, export compensation and the timing of imports and exports can all make bill savings differ from the annual kWh offset percentage.
4. The project price mixes solar with batteries, roofing or electrical work
A bundled project total can be useful for budgeting but misleading for solar price-per-watt comparisons. Battery storage, reroofing, service-panel work and other non-solar scope should be identified separately before comparing two proposals on solar $/W.
If a deduction would equal or exceed the entered project price, stop the normalization and verify whether the project total already excluded that line item. Do not subtract the same scope twice.
5. Financing is presented mainly as a monthly payment
A low payment can come from a long term, a different financed amount, a promotional period, a stepped schedule or other loan structure. Monthly payment by itself is not enough to compare the cost of two solar loans.
Confirm the cash-equivalent project price, what the quoted financed number represents, APR, term, number and frequency of payments, Total of Payments, Finance Charge and any final or balloon payment that is explicitly disclosed. Keep Regulation Z Amount Financed separate from a financed contract price or assumed principal unless the lender documents that relationship.
6. Cash price and financed price cannot be clearly separated
The Consumer Financial Protection Bureau has warned that solar-specific financing can include complex pricing and markups. A homeowner should be able to ask for a cash-equivalent system price and understand what is being financed before comparing APR or monthly payments.
Do not label every difference between two financing numbers as a dealer fee. The contract and lender disclosures control what each number means.
7. A lease or PPA starts low but the escalator and transfer rules are hard to find
A lease payment or PPA energy rate can increase under an annual contract escalator. Even a modest annual increase compounds over a long agreement, so review the starting price, escalation timing, contract term and the full written payment or energy-rate schedule.
Also verify transfer, buyer-assumption, buyout, early-termination and end-of-term terms before relying on a sales summary. These details can matter when the home is sold or refinanced.
8. Equipment is described only by brand or generic technology
A proposal should identify the exact panel and inverter or microinverter models that are expected to be installed. Brand-only descriptions make it difficult to verify module wattage, inverter AC capacity, warranty terms and whether substitutions are allowed.
For battery projects, confirm the exact battery model, number of full units, usable kWh, continuous output and what gateway or control equipment is included.
9. Warranty years are prominent but service responsibility is vague
A long warranty headline does not show what labor, roof penetrations, truck rolls, monitoring, equipment replacement or transfer to a new owner actually covers. Panel product warranties, performance warranties, inverter warranties and installer workmanship warranties are separate obligations.
Ask who handles a service call, which costs are excluded and what happens if the original installer is no longer available.
10. Export limits or utility interconnection requirements are missing from the production story
Some projects operate under explicit export caps, zero-export controls or other interconnection constraints. An export limit is not the same thing as inverter AC capacity, and the difference between the two does not directly equal annual curtailed energy.
If the utility or proposal states an export cap, ask whether the production model includes the actual control behavior and how the system is expected to use or store energy that cannot be exported.
11. Savings depend on one aggressive future utility-rate assumption
Long-term savings projections often compare the solar proposal with a modeled no-solar utility bill. Future utility rates are uncertain, so the assumed annual escalation rate can materially change a 20-, 25- or 30-year savings headline.
Compare more than one escalation scenario and verify the starting utility bill or rate, export-credit treatment, solar degradation and financing assumptions before treating a long-term dollar claim as a forecast you can rely on.
12. You are pressured to sign before you can review the complete agreement
The Federal Trade Commission advises consumers to take time to review solar offers and warns against pressure to sign quickly or claims that hide the real cost of the project. A serious proposal should leave enough time to compare detailed bids and read the contract that actually controls the transaction.
If the salesperson's explanation differs from the written proposal, financing disclosure or contract, get the difference resolved in writing before signing.
A practical order for reviewing a proposal
Start with completeness, then verify the few numbers that drive most comparisons. Keep engineering, pricing, financing and contract checks separate so one attractive headline does not hide a missing field somewhere else.
- Confirm panel count, module wattage and quoted DC system size.
- Confirm first-year production and the assumptions behind it.
- Separate solar-only price from batteries and non-solar construction scope.
- Confirm exact panel, inverter and battery models.
- Review inverter AC capacity and any utility export limit separately.
- Verify cash price and the meaning of every financed amount before comparing loan terms.
- Model lease or PPA escalators and review transfer or buyout terms.
- Read workmanship, roof and equipment warranty coverage rather than comparing years alone.
- Use independent planning references as a cross-check, not as a production guarantee or engineering certification.