REC is one of three panel brands we recommend, and it is the one we reach for when a roof is going to get genuinely hot. That sounds like an odd priority in a region famous for rain. Stay with us — it is the most misunderstood number in solar.
The specification that matters here
Every solar panel loses output as it heats up. The rate is the temperature coefficient, quoted as a percentage of output lost per degree Celsius above the rating condition. A panel rated at -0.29%/°C loses 0.29% of its output for every degree over 25°C.
The REC Alpha Pure-RX comes in at -0.24%/°C. For comparison, the Q CELLS Q.TRON is -0.29%/°C and the Silfab Prime SIL-440 QD is -0.29%/°C. Those are all good numbers. REC’s is the flattest of the three.
Why that matters in the Pacific Northwest
Because a roof is not the air. On a clear July afternoon in Camas with an air temperature of 32°C, the panels on a south-facing roof are running far hotter than that — dark glass, low wind, sun on them all day. And July is precisely when your system is producing the energy that net metering banks to cover your December bill.
Our summers have also changed. Heat events that used to be remarkable now arrive most years, and the Gorge corridor in particular gets hot. A flatter temperature coefficient earns its keep on exactly the days that contribute most to your annual total.
The rest of the specification
- REC Alpha Pure-RX — 450 to 470 W, 21.6% to 22.6% module efficiency.
- Heterojunction (HJT) cells, n-type, 88 half-cut cells, gapless layout, solder-free interconnection. REC claims no light-induced degradation from this construction.
- Warranty — 25-year performance warranty guaranteeing a minimum 92% of nameplate output at year 25, at a warranted 0.25% annual degradation. The 25-year product warranty applies when installed by a REC Certified Solar Professional; the base product warranty is 20 years, so the certified-installer point is not a marketing detail, it is five years of cover.
- Made in Singapore. REC also offers a domestic-content SKU assembled with a mix of foreign and domestic components for projects chasing the domestic-content adder — that is not the same as a US-made panel and we will not describe it as one.
Low light, which is the other half of the story
Temperature coefficient and low-light performance are related but distinct. REC publishes a low-irradiance efficiency curve for the Alpha Pure-RX, and heterojunction cells are broadly recognised for holding efficiency well in weak light. That is a reasonable thing to value in a climate with a long grey shoulder season on either side of summer — though annual output here is still driven far more by long June and July days than by squeezing extra watts out of a dim February afternoon.
A name collision worth clearing up
If you search REC and Washington State you will find REC Silicon, a polysilicon company at Moses Lake that has had a difficult few years and moved to private ownership in 2026. That is a different company. The panel maker is REC Group, owned by Reliance Industries since 2021. The two are not the same business and one’s troubles say nothing about the other. We mention it because the confusion is easy and the conclusion people draw from it is wrong.
Where we would and would not specify REC
Good fit
- South and south-west facing roofs with little shade and full afternoon sun, especially in the Gorge corridor and anywhere that bakes in July.
- Roofs where the usable area is limited and you need the most output per square metre you can get.
- Homeowners who intend to stay put and care about year-25 output rather than year-one price.
Less compelling
- Heavily shaded roofs, where the constraint is a Douglas fir rather than the panel — solve the shading question first, with microinverters or a different array layout.
- North-facing or deeply sheltered arrays that never get hot, where the temperature advantage has little to work with.
- Tight budgets, where Q CELLS or Silfab deliver most of the outcome for less.
If US manufacturing matters to you, this is the one of our three recommended panels that is not made in North America — Silfab assembles modules in Burlington, Washington and Q CELLS assembles in Georgia.
Are REC solar panels good for the Pacific Northwest?
Yes. The Alpha Pure-RX has a -0.24%/°C temperature coefficient, the flattest of the panels we install, which protects output on hot summer days — exactly the production that net metering banks against your winter bill.
What is a temperature coefficient and why does it matter?
It is the percentage of output a panel loses for each degree Celsius above its rating condition. Roof surfaces run much hotter than air temperature on a clear summer day, so a flatter coefficient means more output when your system is generating most.
What is the REC Alpha warranty?
A 25-year performance warranty guaranteeing at least 92% of nameplate output at year 25. The 25-year product warranty applies when installed by a REC Certified Solar Professional; the base product warranty is 20 years.
Where are REC panels made?
The Alpha Pure-RX is made in Singapore. REC also offers a domestic-content SKU assembled from a mix of foreign and domestic components, which is not the same as a fully US-made panel.
Is REC Group the same as REC Silicon in Moses Lake?
No. They are separate companies. REC Group makes solar panels and is owned by Reliance Industries; REC Silicon is a polysilicon producer at Moses Lake, Washington with unrelated ownership and its own difficulties.
Is REC better than Q CELLS or Silfab?
It depends on the roof. REC leads on temperature coefficient, Silfab offers a 30-year performance warranty and Washington assembly, and Q CELLS often wins on value. On a shaded roof, none of those differences matters as much as fixing the shading.
Want to know which panel actually suits your roof, orientation and trees? Call us at 360-313-7190 or request a free quote.
