If you’re collecting solar quotes this fall, you now have a real deadline. It’s December 4. You’re also about to hear a sales pitch that makes it sound roughly five times bigger than it is.
Here’s the actual number, before someone else gives you theirs.
What was signed
On August 6 the White House issued a Section 232 proclamation on polysilicon, the refined silicon every solar cell starts as. Two things happen at 12:01 a.m. on December 4.
A 15% tariff hits imported components made with polysilicon, wafers and cells and finished panels, no matter which country they ship from. And minimum import prices kick in: $21 a kilogram for polysilicon, $100 a kilogram for ingots and wafers, 22 cents a watt for cells, and 38 cents a watt for finished panels.
The 38 cents is the part that reaches your roof. It’s a floor, not a tax. An imported panel can’t be sold below it.
Right now panels assembled in Southeast Asia run about 27 cents a watt. Indian-assembled panels run about 14. American-assembled ones sit around 31.
Translation: the cheapest panels on the market are the ones the floor moves the most. A 14-cent panel and a 27-cent panel both become a 38-cent panel.
What it costs you
That’s where the “40% increase” line is going to come from, and it isn’t wrong. It’s just describing the panel, not the job.
An 8 kW system averaged $20,960 before incentives this year, per EnergySage’s marketplace data. The panels inside that system, at 27 cents a watt, are about $2,160 of it. At the 38-cent floor, about $3,040. Call it $880, plus the 15% on top.
So somewhere around a thousand dollars on a twenty-one-thousand-dollar job. If your installer was sourcing the cheap Indian panels, closer to $1,900.
Real money. About 4% to 9% of the system. Not 40%.
We’ve written before about a solar quote waving a December 31 deadline that wasn’t the buyer’s deadline at all. This one is different. The date is real. The number attached to it, when it arrives in a sales deck, usually won’t be.
Do this
Get three quotes now, while the current panel pricing is still in them. Ask each installer for the module line item in dollars per watt, and ask where those panels are assembled. If they won’t break it out, that tells you something.
Then ask for a written price hold that runs through installation, not through contract signing. A signature in October protects nothing if the panels get bought in January.
Run your own payback math on the solar savings calculator first, and read the solar hub if you’re still deciding whether a system pencils out at all. A thousand dollars of hardware moves a payback period by months, not years.
Do not sign anything the same day someone explains this proclamation to you.
The policy is a deliberate bet: make imported panels cost more, and domestic polysilicon and cell plants get built. Manufacturers asked for it and said so publicly. Whether that pays off nationally is a long argument. The short version for your roof is that the bill lands in December, it’s four figures, and knowing its size is the difference between shopping and being sold.
How Candid Yak makes money. Some of the products we write about pay us if you apply or sign up through our links. That never changes our verdict, our rankings, or the numbers in this article. We call a bad deal a bad deal whether it pays us or not. Some brands shown in our comparison tools are placeholder examples while we finalize partner agreements, and we label them as such.
Sources
- Sec. 232 polysilicon results: The price of all imported solar panels is going up (Solar Power World, August 6, 2026)
- Trump Administration Imposes Section 232 Tariffs and Minimum Import Prices on Polysilicon and its Derivatives (Wiley)
- How Much Does an 8 kW Solar Panel System Cost? (EnergySage Marketplace data, updated June 19, 2026)