You did the smart thing — you got multiple solar quotes. Now you're staring at three proposals with totally different prices, different panels, different warranties, and a salesperson on each end telling you their bid is the best. How do you actually compare them?
This guide walks through the exact framework professional solar consultants use to evaluate proposals. By the end, you'll know which bid is genuinely the best deal — and which ones have hidden problems.
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Analyze My Bids Free →Why solar bids are so hard to compare
Solar proposals are deliberately formatted to make apples-to-apples comparison difficult. Each company has its own template, uses different terminology, hides costs in different places, and presents savings projections with different assumptions. Some companies show you the gross price; others show net after the federal tax credit. Some include the cost of a main panel upgrade; others bury it as a "potential additional cost."
That's not an accident. The harder it is to compare, the easier it is for the highest bid to win on flashy graphics rather than actual value.
The 12 things every solar bid must show you
Before you can compare bids, every proposal needs to clearly state these 12 items. If even one is missing, ask the contractor to add it before you make a decision.
- System size in kW DC (not just panel count)
- Panel make, model, and wattage
- Inverter make, model, and type (microinverter, string, or string-with-optimizers)
- Racking system brand
- Projected annual kWh production in year 1
- Solar offset percentage against your current usage
- Gross price and net price (after tax credit and rebates)
- Cost per watt (gross and net)
- Equipment warranty terms (panel, inverter, workmanship)
- Production guarantee, if any
- Installation timeline with phases
- Itemized incentives (federal ITC, state, utility, co-op)
Start with cost per watt — but don't stop there
Cost per watt ($/W) is the single most useful number for comparing solar bids because it normalizes for system size. A $25,000 bid for a 6 kW system is $4.17/W; a $40,000 bid for a 12 kW system is $3.33/W — the larger system is actually cheaper per unit of capacity.
In 2026, typical residential solar pricing in the U.S. ranges from $2.50 to $4.00 per watt gross (before incentives). Anything above $4.00/W needs justification. Anything below $2.50/W is suspiciously cheap and may indicate budget equipment or a contractor cutting corners.
Read our full breakdown: solar cost per watt explained.
Then check production estimates against reality
The number that determines your actual savings is annual kWh production. Salespeople routinely inflate this number to make the payback period look better than it really is. A bid showing 14,000 kWh/yr from a system that should realistically produce 11,000 kWh/yr will overstate your savings by 27%.
Cross-reference projected production against NREL's PVWatts calculator using your address. If a bid is more than 10% above the PVWatts estimate, ask the contractor exactly how they justify the higher number. More on this in our guide on whether solar production estimates are accurate.
Equipment tier matters more than brand recognition
Solar panels are graded by tier. Tier 1 panels come from manufacturers with strong financial stability, third-party testing, and at least 2% of their production used in major bankable projects. Tier 2 and Tier 3 manufacturers may produce panels that work fine, but their long-term warranty support is less certain.
Same with inverters. Enphase microinverters and SolarEdge optimizers are premium options. String inverters from SMA, Fronius, and Sungrow are solid mid-tier. Avoid no-name inverters — they're the most common point of failure in a solar system.
For the latest equipment landscape, see our guides to the best solar panels for 2026 and the microinverter vs string inverter comparison.
Warranty: read past the headline number
Every solar contractor advertises a "25-year warranty." That number is almost meaningless without the details. The real questions:
- Does the warranty cover labor if a panel fails, or just the replacement panel itself?
- Does it cover roof leaks caused by the racking penetrations?
- Is the warranty backed by the manufacturer, the installer, or a third party like SolarInsure?
- What happens if the installer goes out of business?
A 25-year warranty that doesn't cover labor on a failed inverter could leave you with a $2,000+ bill in year 12. Always read the actual warranty document, not just the proposal summary.
Watch for these 7 red flags
Some warning signs come up in nearly every problematic solar bid. If you see any of these, push back hard or walk away:
- "Today only" pricing — Solar isn't a one-day flash sale. Real proposals stay valid for 30+ days.
- Lease or PPA disguised as a "purchase" — Always confirm: do I own this system at the end?
- Production estimates not tied to your address — Generic PVWatts numbers are a red flag.
- Vague equipment specs — "Premium tier 1 panels" without a make and model is meaningless.
- Federal tax credit shown as a discount — The 30% ITC is a credit you claim on your taxes, not money the installer gives you.
- Big down payment before permits are pulled — Reasonable down payments are 10–30% at contract signing, not 50%+.
- Subcontracted installation by a national chain — Service after the sale gets complicated when the installer isn't local.
Full breakdown: 12 solar proposal red flags to watch for.
The contractor matters as much as the equipment
Two installers can sell identical equipment and deliver completely different outcomes. A great contractor handles permitting cleanly, installs the system right the first time, and is around to honor warranties in 10 years. A bad one can leave you with a leaking roof, failed inspections, and no recourse.
Verify these before signing anything:
- NABCEP certification (industry standard for solar installers)
- State electrical contractor license
- 3+ years in business under the same name
- Real Google reviews (not just on their own site)
- Local presence — not just a sales office
- In-house installation crew, not subcontracted
Side-by-side comparison checklist
When you have your bids in front of you, fill out this for each one. The patterns will jump out fast.
- Gross price / Net price after ITC / Cost per watt (net)
- System kW DC / Panel count × wattage / Inverter type
- Year 1 kWh estimate / PVWatts kWh estimate / Variance %
- Solar offset % / Roof area used
- Equipment warranty (panels / inverter / labor)
- Production guarantee yes/no
- Installation timeline weeks
- Down payment %
- NABCEP certified yes/no
- Years in business / Google review count
- Red flags noticed (count)
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Try the Analyzer Free →Frequently asked questions
How many solar quotes should I get?
At least 3, ideally 4–5. Pricing for the same equipment can vary by 30% or more between contractors. Without multiple quotes, you have no benchmark.
Should I always pick the cheapest solar bid?
No. The cheapest bid often uses lower-tier equipment, includes minimal warranty coverage, or comes from a contractor who'll be hard to reach in 5 years. Compare cost per watt alongside equipment quality and contractor reputation.
What's a fair price per watt for solar in 2026?
$2.80 to $3.50 per watt gross is normal for residential solar in most U.S. markets. After the 30% federal tax credit, that's roughly $2.00–$2.45 per watt net.
How do I verify a solar production estimate is realistic?
Run your address through NREL's free PVWatts calculator. If a contractor's estimate is more than 10% above PVWatts, ask them to justify it with shading analysis or specific design details.