Of the three panel brands we recommend, Silfab is the one with the shortest supply line to your roof. Its modules are assembled in Burlington, Washington — roughly 150 miles north of us, in the same state, in the same weather. For a lot of our customers that matters, and it happens to come attached to the longest performance warranty of the three.
The Washington connection, stated accurately
Silfab operates a module assembly plant in Burlington, Washington, which produces panels in its Prime series. It also runs a facility in Fort Mill, South Carolina that does both cell and module manufacturing.
Two honest clarifications, because “American made” gets stretched in this industry. The Washington plant does module assembly, not cell manufacturing — cells are a separate step, and Silfab’s cell production is in South Carolina. And the company previously had a Bellingham, Washington site that it was reported to be leaving in 2024, so if you find an old Bellingham address in a search result, Burlington is the current Washington location.
The current lineup
Silfab Prime
- SIL-440 QD — 440 W, 22.6% module efficiency, n-type Tunnel Contact cells, 108 half-cells, temperature coefficient -0.29%/°C.
- Also SIL-420 and SIL-430 QD in the same n-type family, plus older HC and HC+ models at lower efficiency, around 20.2% to 20.7%.
Silfab Elite
The flagship line — SIL-380 BK, SIL-410 BG and SIL-420 BG — using a back-contact cell design with the interconnections hidden behind the cell. The SIL-420 BG is 420 W at 21.9% efficiency. Back-contact panels are the cleanest-looking modules on the market, which matters if the array is going on a street-facing roof.
We have deliberately not quoted a temperature coefficient for the Elite line here, because we could not confirm a published figure and we are not going to invent one. If Elite is on your shortlist we will pull the current datasheet for the specific model and show you the real number.
The warranty, which is the strongest of the three
On the Prime SIL-440 QD, Silfab publishes a 25-year product warranty and a 30-year performance warranty, guaranteeing at least 90.8% of nameplate output at year 25 and at least 89.3% at year 30.
That extra five years is not a gimmick. A solar array installed today in Vancouver will plausibly still be on that roof in 2056, and the difference between a 25-year and a 30-year performance guarantee is five years at the end of the system’s life when degradation questions actually arise. Silfab markets the same terms across the Elite line, though we have only directly confirmed the specific percentage figures on the Prime datasheet.
How it performs on a Pacific Northwest roof
At -0.29%/°C, the Prime QD line sits level with Q CELLS and slightly behind REC on heat. In practical terms, on a typical Vancouver or Portland roof at valley elevation, that difference is small — it becomes worth paying attention to on a hot south-facing roof or in the Gorge corridor, and it barely registers on a north-facing or well-ventilated array.
N-type cells matter more than the headline efficiency for a system you plan to keep. They are less prone to the light-induced degradation that affected older p-type panels in their first years, which is a difference you notice in year fifteen rather than year one.
The Elite line and shade
Back-contact construction is generally associated with good behaviour under partial shading, which is the single most relevant characteristic on a Clark County lot with mature conifers. We would not push that argument beyond what we can support with a datasheet — and on a genuinely shaded roof, module-level electronics do far more for you than cell architecture does.
One thing you should know about the company
Silfab had a difficult 2026 at its South Carolina plant: two chemical incidents in March 2026 led to a state shutdown order, a zoning ruling went against solar cell manufacturing at the site and was upheld on appeal, and production was halted again in August 2026 for supply and maintenance reasons.
We have found no comparable problems reported at the Washington facility, and we think it would be misleading to imply otherwise. But it would also be misleading to write a page about Silfab in 2026 and not mention it. Silfab is privately held, so there are no public financials to point you at either way.
Where we would specify Silfab
- Homeowners who want the longest performance warranty available from the panels we install.
- Anyone who cares about North American manufacturing and wants the closest thing to a locally made panel — a module assembled in Washington State, on a Washington roof.
- Street-facing arrays where the Elite line’s back-contact appearance is worth the premium.
- Long-horizon owners, where n-type cells and the year-30 guarantee are the point.
For comparison, REC leads on temperature coefficient and Q CELLS is usually the value choice with US cell and module manufacturing in Georgia.
Are Silfab solar panels made in Washington?
Silfab assembles modules at a plant in Burlington, Washington. Cell manufacturing happens at its Fort Mill, South Carolina facility, so the Washington operation is module assembly rather than full manufacture.
What is the Silfab warranty?
On the Prime SIL-440 QD, Silfab publishes a 25-year product warranty and a 30-year performance warranty, guaranteeing at least 90.8% of nameplate output at year 25 and 89.3% at year 30.
Are Silfab panels good for the Pacific Northwest?
Yes. The Prime QD line uses n-type cells at 22.6% efficiency with a -0.29%/°C temperature coefficient, and the 30-year performance warranty is the longest among the panels we install.
What is the difference between Silfab Prime and Elite?
Prime uses n-type Tunnel Contact cells and is the mainstream line. Elite uses a back-contact cell design with hidden interconnections, giving the cleanest appearance, at a higher price.
Did Silfab have manufacturing problems in 2026?
Yes, at its South Carolina plant — two chemical incidents in March 2026 led to a state shutdown order, a zoning ruling went against cell manufacturing at that site, and production halted again in August 2026. No comparable issues were reported at the Washington facility.
Is Silfab better than Q CELLS or REC?
Silfab leads on warranty length and North American assembly, REC on temperature coefficient, and Q CELLS often on value. The right answer depends on your roof, your budget and how long you plan to stay.
Want a quote using panels assembled in your own state? Call us at 360-313-7190 or request a free quote.
