How to Compare Solar Installation Bids (And Not Get Burned by the One That Looks Cheapest)

Two quotes for the same 8 kW solar installation: $24,000 and $31,000. The math looks easy — $3.00/watt versus $3.88/watt, take the cheaper bid. But cost per watt tells you nothing about whether the lower-priced installer holds an electrical contractor license to pull a permit, whether the production estimate has been inflated to make the payback look faster than it is, or whether the financed price has a 20–30% dealer fee buried in it that adds thousands before you sign.

This guide covers how to normalize solar bids by cost per watt, how to verify production estimates against real irradiance data, how to expose dealer fees hidden in financed proposals, and — the question most solar comparison guides skip entirely — how your installer's license status determines whether you qualify for the 30% federal tax credit that changes the net cost of every bid by thousands of dollars.

Why do solar quotes vary so much from each other?

Solar quotes vary because proposals differ in system size in kW, panel brand and efficiency tier, inverter type, annual production guarantee in kWh, permit inclusion, and whether you are seeing a cash price or a financed price with a 20–30% dealer fee layered in. Two quotes that appear to compare the same system often are not quoting the same thing.

Five variables create the most significant price gaps between solar proposals:

• Panel brand and efficiency: Tier 1 panels from manufacturers like REC, Panasonic, SunPower, and Q CELLS carry a premium over commodity panels — but a commodity panel at $2.80/watt and a Tier 1 panel at $3.20/watt are not the same product over a 25-year roof exposure.
• Inverter type: Microinverters (Enphase) and power optimizers (SolarEdge) cost more than string inverters but produce more energy in shading conditions and carry longer warranties.
• System size in kW DC: A proposal quoting 7.5 kW and one quoting 8.5 kW are not comparable on total price alone. Normalize to cost per watt first.
• Production guarantee: Whether the installer guarantees a minimum annual kWh output or just the equipment is a major warranty distinction.
• Permit inclusion: Some bids include permit and inspection fees; others list them as “additional.” Ask directly.

The financed price versus cash price distinction is separate from all of these. The 2026 national average cost for residential solar is $2.95–$3.20 per watt before incentives, according to NREL's 2024 Solar Industry Update. Arizona runs lower at around $2.40–$2.60/watt due to high installer density; high-cost states like Connecticut and New Hampshire run $3.10/watt or above. If a quote falls significantly outside these ranges, the first question is what that quote is actually quoting.

What is cost per watt and how do I use it to compare solar bids?

Cost per watt is total system price divided by the system's DC capacity in kilowatts multiplied by 1,000. An 8 kW system quoted at $25,600 is $3.20/watt. Use it as a normalizing metric only — it removes system size as a variable so you can compare bids for different-sized systems on equal footing.

The formula: Price ÷ (kW × 1,000) = $/watt. A $22,000 quote on a 7.5 kW system is $2.93/watt. A $28,000 quote on a 9 kW system is $3.11/watt. Once you have both on a per-watt basis, the size difference stops distorting the comparison.

2026 benchmarks: $2.40–$2.60/watt in Arizona, $2.95–$3.20/watt as the national average, and $3.50+/watt for premium installers with longer workmanship warranties or high-end equipment packages. A quote well below $2.50/watt in a non-competitive market or well above $4.00/watt without an explanation of what is premium in the package is worth questioning.

What cost per watt does not capture: equipment tier, production guarantee, warranty depth, dealer fee in financed proposals, permit inclusion, and — most importantly — whether the installer holds the electrical contractor license your state requires to pull a permit. A $2.80/watt quote from an unlicensed installer and a $3.20/watt quote from a licensed one are not close in actual net cost once ITC eligibility is factored in.

Typical residential systems run 6–10 kW, with gross costs of $18,000–$32,000. After the 30% federal Investment Tax Credit, net costs run $12,600–$22,400 for qualifying installations.

What should every solar proposal include?

A complete solar proposal must specify system size in kW DC, estimated annual production in kWh, panel brand and model, inverter brand and type, total gross price, net cash price after incentives, whether permits and inspections are included, and full warranty terms for equipment, production, and labor.

Any proposal that does not specify panel make and model, inverter type, and annual kWh production estimate is missing the information you need to evaluate it. Ask the installer to add those details in writing before you compare.

The complete checklist for a solar proposal:

• System size: kW DC and kW AC (DC capacity is what installers quote; AC is what reaches the grid)
• Panel make, model, and efficiency rating (Tier 1 manufacturers: REC, Panasonic, SunPower, Q CELLS)
• Inverter make, model, and type (string inverter, microinverter, or power optimizer)
• Annual production estimate in kWh/year (with the tool used to generate it)
• Gross price before incentives
• Net cash price after the 30% federal ITC and any applicable state incentives
• If financed: cash price, financed price, and dealer fee disclosed separately
• Permit and inspection inclusion — named as a line item, not buried in “installation costs”
• Roof penetration warranty (how long; who covers labor if a penetration leaks?)
• Labor warranty in years (minimum 5 years; 10+ is standard among larger installers)
• Production guarantee — does the installer guarantee a minimum annual kWh output?
• Utility interconnection: timeline and who manages the application

If a proposal lists “standard panels” or “TBD equipment,” that is not a real bid. Equipment substitution after signing is one of the most common sources of solar disputes.

How do I sanity-check a solar production estimate?

Use NREL's free PVWatts calculator at pvwatts.nrel.gov. Enter your address, system size, and panel tilt. PVWatts returns an estimated annual kWh output based on actual historical irradiance data for your location. A realistic estimate is 1,100–1,500 kWh per kW installed per year; above 1,700 kWh/kW is almost certainly inflated.

Step-by-step: go to pvwatts.nrel.gov, enter your ZIP code, enter the system capacity in kW DC from the proposal, select the array type (typically fixed roof mount), and enter the tilt angle the installer specified. PVWatts will return an estimated annual kWh output. Divide that by the system's kW capacity to get your kWh/kW benchmark.

A 7 kW system promising 12,000 kWh/year works out to 1,714 kWh/kW — which is above the realistic range for nearly all U.S. locations outside the Southwest. If PVWatts returns 9,800 kWh/year for the same setup and location, the proposal is inflated by roughly 20%. That inflated estimate may be driving a shorter payback projection and a higher monthly savings claim.

Watch for this language in proposals: “offset 110% of your current bill” without showing the kWh math. The only way to evaluate an offset claim is to compare the proposed annual kWh output to your actual annual consumption from your utility bill. If the installer can't show you that math in writing, the number is marketing.

What is the dealer fee and how does it affect financed solar quotes?

A dealer fee is a markup — typically 20–30% — that solar lenders charge installers and that installers pass through to the customer in the financed quote. A $25,000 system with a 25% dealer fee becomes a $31,250 financed price. The fee is often invisible in the proposal unless you ask for both the cash price and the financed price directly.

Here is how it works: the installer sells the job at the financed price ($31,250), the lender advances that amount, and the installer pays the lender's dealer fee ($6,250) back over the loan origination. From the customer's perspective, they signed for $31,250. If they had paid cash, the same job was $25,000. The difference — $6,250 — is the dealer fee expressed as a higher loan balance.

The 2026 market range for dealer fees is 20–30%, with some lenders going to 35%. On a $25,000 system, that is $5,000–$8,750 added to the financed price. Ask every installer for both the cash price and the financed price on the same scope. The difference is the dealer fee, whether they disclose it by name or not.

This matters for ITC calculation: the federal tax credit is based on what you paid, not the cash value of the system. If you financed a $31,250 job, you may calculate your 30% ITC against the full financed amount. Consult a tax professional on your specific situation, but understand that the dealer fee inflates the basis and ultimately the system cost you are carrying.

What is the federal solar tax credit and why does the installer's license status matter?

The federal Investment Tax Credit gives you a 30% credit against federal tax liability for a qualified solar installation. To qualify, the installation must be permitted. Permits require a licensed contractor in virtually every jurisdiction. An unlicensed installer cannot pull a permit, and an unpermitted installation disqualifies the ITC.

The trap works like this: an unlicensed installer offers a lower cash price because they carry less overhead — no license fees, no bond, no workers' compensation. The savings look real upfront. But an unlicensed installer cannot pull the electrical permit your jurisdiction requires. Without a permit, the installation does not pass inspection. Without a completed, inspected installation, it does not qualify as “placed in service” under IRS Form 5695 — the form you file to claim the ITC.

The dollar math: on a $28,000 system, the 30% ITC is $8,400. Compare the two scenarios. Licensed bid at $28,000 minus $8,400 ITC equals $19,600 net. Unlicensed bid at $25,000 minus zero ITC equals $25,000 net. The “cheaper” bid is $5,400 more expensive after incentives. On a larger system, the gap widens further.

Solar installations typically require both a roofing permit and an electrical permit. The electrical permit requires an electrical contractor license in most states. A solar company that holds a general contractor license but not an electrical contractor license may not be authorized to pull the electrical permit in your jurisdiction.

Before you sign, look up the installer on your state licensing board or run a check at CheckLicensed.com to confirm they hold the active electrical contractor license your state requires. For a full breakdown by state, see our guide on what license type your state requires for solar electrical work.

How do I verify a solar installer's license and complaint history?

Look up the installer's business name and license number on your state's contractor licensing board website. Confirm the license is active, covers electrical work, and has no disciplinary history. For BBB complaint history, the most predictive categories for solar are billing disputes, failure to honor warranty, and permit non-completion.

What to look for on a state board search: Active versus Inactive, Suspended, or Expired status. Electrical classification — verify the license type explicitly covers electrical contractor work, not just general construction. Expiration date. And the disciplinary actions or complaint tab, which most state boards maintain separately.

Check both the company's license and the qualifying individual named on the license. Solar companies frequently change the qualifying individual when that person leaves, and the new qualifier may not have the same experience level. The qualifying individual's license status is what actually authorizes the permit pull.

A complaint pattern of “failure to complete interconnection” or “permits not finalized” is a specific red flag in solar — it means the installer collected payment, installed panels, and did not complete the permitting and utility interconnection process that is required before the system legally operates and the ITC clock starts.

CheckLicensed.com pulls license status and complaint history in one step — enter the installer's name and state before you sign. For more on warning signs before hiring, see our guide on signs of a solar installer running a scam.

What are red flags in a solar bid?

Red flags in a solar bid include a production estimate above 1,700 kWh/kW/year without location-specific justification, a financed price with no cash equivalent disclosed, no permit line item or vague “permit coordination” language, a warranty that excludes labor costs, and any pressure to sign before the proposal is in writing.

The full red flag list:

• Production estimate above 1,700 kWh/kW/year — check against pvwatts.nrel.gov for your ZIP code
• No panel or inverter model specified (“standard panels” or “TBD equipment”)
• Financed price presented with no cash price disclosed
• “Permit coordination included” without confirming the installer pulls the permit themselves
• Labor warranty under 10 years from a major installer, or no written labor warranty at all
• No utility interconnection timeline stated
• Full or majority payment required before installation begins
• Verbal-only production guarantees — any guarantee not in writing is not a guarantee
• Urgency pressure: “this rebate expires this week” or “we can only hold this price through Friday”
• No mention of license number in the proposal or contract

The urgency flag is worth its own note. Solar incentive structures in 2026 are stable — the 30% federal ITC has no expiration date in the near term. An installer claiming a specific rebate expires this week is either misinformed or manufacturing pressure to prevent you from doing the verification steps above.

Should I just take the lowest solar bid?

No. Take the lowest net-of-ITC bid from a licensed installer with clean complaint history. A bid $3,000 lower from an unlicensed contractor costs $5,000–$8,000 more after losing the ITC. The right comparison is: normalized cost per watt, plus verified license status, plus ITC eligibility, plus warranty depth.

The correct decision framework: normalize bids to cost per watt to remove system size as a variable. Verify each installer holds an active electrical contractor license in your state. Apply the 30% ITC to each licensed bid to find the net cost. Then compare net cost against warranty depth and production guarantee.

When the cheapest bid is legitimately cheapest: the installer is licensed with a clean complaint history, the equipment tier is equivalent to other bids, the production estimate checks out against PVWatts, and the lower $/watt reflects operational efficiency rather than scope cuts. Those bids exist and are worth taking.

When to walk away: unlicensed installer, no written contract before signing, no permit included, pattern of permit non-completion complaints, or a financed quote with no cash price disclosed. Any one of these converts an apparent savings into a real loss.

CheckLicensed.com/compare-bidslets you organize multiple quotes and run a license check on each installer in the same workflow — run it before price enters the final comparison.