Audit the solar quote.

System size · price · production · credit timing

Start auditSize system

The proposal is the starting point. The assumptions are the product.

The audit desk

What we check inside the quote.

A real residential proposal. Seven inputs. Each line earns a verdict against public data — and where we can't see the answer, we say so.

Run the full auditRead the methodology
Residential solar proposalFile № 8.4kW·2026
A real quote, audited.Internal audit · live
System size8.4 kW DCRecorded
Cash price$31,800In range
Cash $/W$3.79LBNL band
Financed price$38,200Likely markup
Production est.10,900 kWh / yrVerify
Payback claim7.2 yrsPlausible
Tax credit30%, 2026§25D ended

What this audit cannot seeRoof condition, future shading, utility rate design, installer workmanship, your tax liability, HOA · permitting delays. The calculator catches what's on paper.

Price

Cash price vs financed price. Find the dealer-fee gap before the monthly payment distracts you.

Loan math

Production

Stress-test the kWh claim against a public production model.

30%0%

Incentives

Check whether a 2026 proposal is still subtracting a federal credit you can claim.

Eligibility
Run the math

Each assumption gets its own test.

All calculators →

Solar quote calculator

Paste the seven numbers on the proposal. Get the line-by-line verdict.

Audit the quote →

Solar panel calculator

How many panels you actually need — not how many the salesperson can fit.

Size the system →

Solar payback calculator

Payback math with the assumptions exposed. Move the escalator, watch the year change.

Stress-test payback →

Solar loan calculator

Strip the dealer fee out of the cash price. Find out what the loan really costs.

Find the markup →

Solar tax credit checker

Is the 2026 proposal still pricing the 30% credit? Find out before you sign.

Check the credit →

Solar battery calculator

Backup product or savings product? Different math. Don't let one quote claim both.

Split backup vs savings →
The reading list

Read before you sign.

All guides →
  1. 01
    Quote audit

    How to read a solar quote

    Five numbers decide whether the math holds up. Where each comes from — and how each misleads.

  2. 02
    Pricing

    Solar cost per watt

    What “fair” looks like in 2026, and where in a financed quote the markup likes to hide.

  3. 03
    Financing

    Solar loan calculator

    Compare cash price with financed total and separate stated APR from hidden markup.

  4. 04
    Utility policy

    Net metering vs net billing

    Two compensation models, two different bills. The one your utility uses changes the payback by years.

  5. 05
    Bill reality

    Why your solar bill may not go to zero

    Fixed charges, winter mismatch, and the asterisks proposals quietly drop. Yes, you'll still get a bill.

  6. 06
    Sales pressure

    Solar sales red flags

    Disappearing discounts. “Today only” incentive pricing. The pressure tactics worth walking out on.

The public-data spine

Benchmarked against public data, not installer promises.

Every benchmark, production estimate, and tax-credit ruling on this site cites a primary source — named inline on the page that uses it, with a verification date. No affiliate lookups, no installer matching, no lead form.

  1. 01NREL PVWattsVisit ↗Annual production estimates by ZIP
  2. 02EIA Electric Power MonthlyVisit ↗Residential utility-rate history + escalator reality
  3. 03IRS / DOEVisit ↗§25D eligibility + consumer-protection framing
  4. 04LBNL Tracking the SunVisit ↗Installed cost benchmarks, dealer-fee gap data
  5. 05DSIREVisit ↗State + utility incentive lookup (pointer only)
Full methodology + source list →
After the sales visit

The questions that arrive after the salesperson leaves.

The proposal still assumes the 30% federal tax credit. Can I really use it in 2026?
If your installation finishes in 2026 or later: no. The federal Residential Clean Energy Credit ended for systems placed in service after December 31, 2025 per the IRS Form 5695 (2025) instructions1. The 2025 federal law that ended the residential credit set that cutoff. “Placed in service” means the system is fully installed — not the day you signed, not the day a deposit cleared, not the day a permit was pulled. If an installer is still quoting 30% on a 2026 install, ask which section of the Code authorizes it.
Why are the cash price and financed price so different?
Because the cash price on a financed quote usually isn't the cash price. Many financed solar proposals inflate the cash figure by 15–35% and use that gap to subsidize a teaser-rate loan. The headline APR looks great; the dealer fee is what's actually paying for it. Ask for the cash-only price separately, divide by your system's DC kW, and compare $/W across quotes.
Will the system actually pay for itself in 7 years?
Maybe — and the difference is three numbers the proposal didn't show. Payback is a 25-year forecast resting on a production estimate, your current utility rate, and an assumed rate escalator. Recent EIA data2 shows residential rates rose 10.2% year over year through March 2026, but the 10-year trend is closer to 2–3%. Rerun the proposal with a conservative escalator and an aggressive one. If the payback year shifts by more than two, the headline number was a guess.
Should I get more than one solar quote?
At least three. The DOE Homeowner's Guide to Going Solar3calls pushy sales tactics a red flag and recommends NABCEP-certified installers. Three quotes also reveal the $/W spread in your area — the cheapest read on local pricing you'll get for free. One quote isn't a market.
Will my electric bill actually go to zero?
Usually not. Three things keep a bill alive: fixed charges (connection fees, basic service), seasonal mismatch between summer production and winter use, and net-metering policies that credit your exports at less than retail rate. Bill savings are real. “Zero bill” is a sales line.
Do I need a battery?
Depends what you're buying. Batteries are excellent backup products. They're mediocre savings products in most markets — the financial payback needs steep time-of-use rate spreads or frequent outages to make sense. Don't let an installer bundle a battery into a payback table that claims both savings and resilience at the same time.
  1. 1. IRS Form 5695 (2025) instructions. Verified 2026-05-22: “You can't claim residential clean energy credits for expenditures made after December 31, 2025.” irs.gov/instructions/i5695 ↩
  2. 2. EIA Electric Power Monthly, Table 5.6.A — Average Price of Electricity to Ultimate Customers by End-Use Sector. March 2026 residential average: 18.83 ¢/kWh, +10.2% year over year. 10-year residential rate trend: ~2–3% per year. Released 2026-05-21. Verified 2026-05-22. eia.gov/electricity/monthly ↩
  3. 3. U.S. Department of Energy, “Homeowner's Guide to Going Solar.” Lists four consumer-protection red flags: pushy sales tactics, uncertified installers, opaque financing, and reporting paths for bad actors. energy.gov/eere/solar/homeowners-guide-going-solar ↩

Ask a TrueSolarCost question

Quick answers about TrueSolarCost's calculators, the public-data benchmarks, and how to read a residential solar proposal. Free, no signup. Not personalized advice — for tax-position questions talk to a CPA, for roof/structural questions talk to a roofer or engineer, for utility-rate questions talk to your utility.

Hi, I'm the TrueSolarCost assistant. I answer questions about how to read a residential solar proposal, what the calculators on this site compute, and what the public-data benchmarks (NREL PVWatts, EIA, IRS, LBNL, DOE, DSIRE) mean for the numbers in your quote. I'm not a tax professional, CPA, structural engineer, or licensed installer — for tax-position decisions talk to a CPA, for roof-condition or structural questions talk to a roofer or engineer, for utility-rate or interconnection specifics talk to your utility.