Research-backed solar guide

Solar proposal red flags

Identify warning signs before a vague or overhyped proposal costs you money.

Part of the: Choose and compare solar installers

SolarGabay Editorial Sources reviewed Updated July 20, 2026 · 13 min

Author

SolarGabay Editorial Team — independent consumer-focused writers who translate technical sources into practical homeowner guidance.

Technical review

Reviewed against the published methodology, source hierarchy, and stated limitations. This is educational guidance, not site-specific engineering.

Update history

Last reviewed July 20, 2026. Corrections are logged through the public corrections process and material changes update this date.

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Practical answer

What you should know first

A solar proposal can look polished and still be weak. Red flags usually appear when the proposal is vague about equipment, exaggerated about savings, or silent about exclusions and support. Buyers should treat clarity as a sign of competence.

The most serious red flags are missing assumptions, missing scope, and pressure to decide before verification.

Decision map

Test every major claim

Can it be measured?

System size, annual generation, self-consumption, backup runtime, and savings assumptions.

Is it in scope?

Equipment, roof work, protection, permits, monitoring, training, and handover documents.

Who owns the risk?

Leaks, delays, rejected applications, lower output, faults, and warranty labor.

The variables that matter

A proposal that does not specify actual equipment models is difficult to evaluate.

Very high savings claims without a clear basis should trigger caution.

Missing roof, permit, or protection scope often leads to extra charges later.

Pressure tactics and “today only” pricing are a bad fit for a long-life infrastructure purchase.

Technical red flags

Watch for proposals with no roof layout, no model numbers, no annual generation, no loss assumptions, no backup-circuit definition, or no explanation of how the array and inverter were sized.

A single savings percentage is not an engineering result. Production should be stated in kWh and linked to location, orientation, shading, and system losses.

Workers assembling roof framing before permits and structural approval — The most serious red flags are claims that cannot be traced to equipment, site data, calculations, written scope, or a responsible party.

No site information but an exact savings promise.

Oversized battery or array with no load analysis.

Unclear protection, grounding, mounting, or commissioning scope.

[1] U.S. Federal Trade Commission [2] U.S. Department of Energy [3] U.S. Department of Energy

Commercial red flags

FTC guidance warns against pushy tactics, immediate-signature pressure, and contracts that consumers cannot review. Other warning signs include a financed price with no cash comparison, vague exclusions, and verbal warranty promises.

A professional proposal should become clearer when questioned. If basic questions produce irritation or changing answers, the risk is not resolved by a discount.

“Today only” pricing on a complex infrastructure purchase.

Large upfront payment before final design or permits.

Savings or incentive claims presented as guaranteed.

[1] U.S. Federal Trade Commission [2] U.S. Department of Energy [3] U.S. Department of Energy

Worked example

“Zero bill” without a load and tariff model is a warning

Fixed charges may remain, usage can grow, exports may be credited differently from imports, and seasonal production changes. A credible proposal shows assumptions and a range instead of a guarantee.

Unqualified guarantees transfer hidden risk to the buyer.

Decision rule

Stop the purchase when a seller refuses exact models, assumptions, exclusions, cash price, or written responsibility for failures.

Practical checklist

Look for a clear scope, line items, and system assumptions.

Ask for written clarification of anything vague before you proceed.

Be cautious if key technical questions are met only with sales language.

Take extra time when the proposal seems exciting but oddly incomplete.

Evidence, scope and limitations

A proposal should reduce uncertainty, not rely on it.

International references are used for engineering and consumer principles. Philippine utility procedures, tariffs, permits and legal requirements must be confirmed using current local rules.

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