Solar panels & cells: what to buy, what it costs, what is hype
Plain-English guides built on manufacturer datasheets, IRS text and published reports, with anything we could not verify labeled as such.
Five pages, from "which panel?" to "is the future here?"
Types compared
PERC, TOPCon, HJT, back-contact, thin-film and flexible, with datasheet efficiency.
Compare types →Cost per watt
Retail vs installed price, 2026 benchmarks, tariffs and the ended credit.
See the numbers → Free toolRoof-fit calculator
How many panels fit, and how two panel models compare on your roof.
Open calculator →Lifespan & warranty
Product vs performance coverage, degradation, and independent test results.
Read the guide →Perovskite tracker
Lab record or product you can buy? A dated tracker with unverified claims flagged.
Check status →Three things that changed the buying picture in 2026
1. The homeowner credit is gone
The 30% federal credit for homeowner-owned solar (Section 25D) does not apply to expenditures after December 31, 2025. The IRS treats an expenditure as made when the original installation is completed, so a 2025 payment for a 2026 installation did not preserve it. Our incentives guide covers what still exists by state, and our lease calculator compares ownership options.
2. A new tariff takes effect December 4, 2026
A proclamation signed August 6, 2026 sets minimum import prices on covered polysilicon products (modules at $0.38/W, cells at $0.22/W) plus a general 15% additional duty. It applies to imports, not retail prices, and any effect on a homeowner's quote is indirect and varies by installer.
3. Efficiency headlines outran what is on roofs
A 35.5% tandem cell announced in July 2026 is a research device. Commercial residential panels we checked document module efficiencies of roughly 20% to 23.5%. See the tracker for the difference.
Our rules. Every figure on these pages has a source link. We do not invent prices or statistics, and where a claim could not be confirmed from a primary source we label it UNVERIFIED instead of guessing. Manufacturer figures are rated or warranted values, not measured field results.
Frequently asked questions
What are the main types of solar panels?
For rooftops: PERC (older mainstream), TOPCon (current mainstream), heterojunction and back-contact (premium efficiency). Thin-film and flexible panels exist for specialist uses. Compare real module efficiency, not marketing labels.
Is the 30% federal solar tax credit still available?
Not for homeowner-owned systems completed after December 31, 2025, according to the IRS. Paying in 2025 for a 2026 installation does not preserve it.
How much do solar panels cost per watt?
Installed systems run about $2.60/W on EnergySage's marketplace and about $3.36/W nationally in Q2 2026, before incentives. Panel-only prices are lower and vary by quantity and freight.
How long do solar panels last?
Performance warranties commonly run 25 to 30 years, and a long-running NREL review found a median degradation of about 0.5% a year.
Can I buy perovskite or tandem solar panels yet?
We found no verified US homeowner product with an established warranty. Tandem modules have shipped commercially to utility-scale customers, and lab-cell records are not products.
Ready to see what solar could do for your bill?
Use our state calculators and financing tools to estimate a rooftop system's cost and savings.
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