All guides
The audit, written out.
Eleven plain-English guides for homeowners auditing a residential solar proposal. Every guide is sourced inline from NREL, LBNL, EIA, IRS, or DOE primary data. No installer marketing prose. No government bulletin. Magazine voice, calm and specific.
Updated May 16, 2026.
Cluster
Quote audit
What to look for on a proposal before signing. Start here if you have a quote in hand.
How to read a solar quote
Five numbers decide whether the math holds up. Here's where each one comes from — and how each one misleads.
Solar sales red flags
DOE's four consumer-protection red flags plus three 2026-specific tells. With the sentence that ends the kitchen-table meeting.
Questions to ask before signing
Twelve sourced questions for the kitchen-table meeting — production guarantees, dealer-fee disclosure, placed-in-service commitments, lien language, the cancellation window.
Do I need a new roof before solar?
Solar panels last 25–30 years; asphalt shingles last 15–25. When the roof gives up first, you pay $1,500–$3,500/kW to remove and reinstall. Decision matrix by roof age and material.
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Money & finance
The pricing math the salesperson didn't show. Cash, financed, or in between.
Solar cost per watt
Berkeley Lab's 2023 data shows state-median residential $/W between $3.20 and $5.20. Where your number lands — and where the markup hides.
Solar loan dealer fees
Why a 'low APR' solar loan can cost more than cash. The dealer-fee structure LBNL documents, explained.
Solar payback mistakes
Rate escalator. Production estimate. Degradation curve. Compensation model. Most proposals get three of the four wrong by enough to move the headline year.
Lease vs PPA vs loan vs cash
Four ways to pay for residential solar — what each means for ownership, the tax credit, the bill, and the next 25 years. Comparison table plus a decision matrix.
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Compensation & bill
Where the savings actually come from — and where they don't.
Net metering vs net billing
When your panels produce more than your home uses, what's that kWh worth? The answer changes the payback by years.
Why your solar bill may not go to zero
Fixed charges, seasonal mismatch, and net-metering policy — three reasons 'eliminate your electric bill' rarely happens.
Are solar batteries worth it
A 13.5 kWh battery costs $14–17K installed. When it earns that back — and when it's a resilience product the quote is pretending is also a savings product.
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.