Skip to main content
REC REC420AA Pure-R
REC Brand review

REC420AA Pure-R

420 Wp HJT Bifacial
ComparePV verdict

Middle of its segment, short guarantee

Rank 9,228 of 14,129
Compare panels Datasheet PDF
Power (Wp)
420
Weak · bottom 23%
Efficiency (%)
21.80
Typical · median 22.20%
Density (Wp/m²)
217.2
Weak · bottom 24%
Temp (%/°C)
-0.240
Typical · median -0.240
Weight (kg)
21.5
Typical · median 23.0 kg
Warranty (yrs)
25
Weak · bottom 8%

The REC Alpha Pure-R series redefines performance standards through the use of advanced heterojunction (HJT) cells, which combine the benefits of crystalline and thin-film silicon. The innovative, gapless cell layout allows for maximum active surface density, translating into more power generated from every square meter of the roof. This is an ideal solution for homeowners with limited installation space who are looking for maximum energy yields. These panels effectively eliminate the problem of performance drops in high temperatures and partial shading, which is possible thanks to the unique division of the module into four independent sections. REC Alpha Pure-R also features a breakthrough completely lead-free construction, making it one of the most eco-friendly premium products on the PV market. The product is dedicated to demanding prosumer installations, where elegant All-Black aesthetics must harmonize with uncompromising mechanical durability. It stands out from the competition with an optimized version of Twin Design technology, which ensures stable system operation even in difficult weather conditions. Choosing this series is an investment in energy security and the highest component operating standards for at least 25 years of use, guaranteeing the lowest rate of power degradation over time.

Ranking

113 panels in the segment HJT 400-450 W
Metric This panel Median Position in segment Overall rank
Module efficiency 21.80% 22.20% Typical 7,085
Power density 217.2 221.6 Weak · bottom 24% 7,462
Temperature coefficient -0.240 -0.240 Typical 13
Weight per kWp 51.2 52.4 Typical 4,591
Performance warranty 25 yrs 30 yrs Weak · bottom 8% 9,912
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

5 positive · 4 caution
Best for

Residential, shaded-installations and hot-climate.

Not ideal for

Owners who want a long output guarantee and roofs where every square metre has to count.

Watch-outs
25 year performance warranty

Bottom 8% of the HJT 400-450 W segment, against a median of 30 yrs. Ranked 9,912th in the whole database.

217.2 watts per square metre

Bottom 24% of the HJT 400-450 W segment, against a median of 221.6.

What owners get
High-efficiency HJT cells

Heterojunction (HJT) cell technology reaches up to 22.3% efficiency, placing the series at the top of its peer comparables - ahead of Silfab Elite (21.9%) and Boviet GAMMA (19.8%) - with up to 430 Wp and a lower temperature coefficient than conventional PERC cells.

92% power warranty at year 25

REC guarantees a linear degradation of only 0.25% per year, resulting in at least 92% of nameplate power at year 25 - one of the lowest degradation rates in the premium segment, backed by the industry-standard 25-year product and power warranty.

Lead-free construction

Alpha Pure-R is among the first premium series to be fully lead-free in its lamination, easing compliance with tightening environmental regulations (e.g., RoHS/REACH) and simplifying end-of-life module recycling.

Tier-1, bankable manufacturer

REC (Norway, founded 1996) is classified as a Tier-1 bankable manufacturer, which eases project financing and lowers investor risk compared to less established brands among the peer comparables.

Partial shading resilience

The module's four-way cell segmentation limits output loss under partial shading or soiling compared to conventional three-way split panels, which is valuable for roofs with irregular geometry.

Trade-offs
2022-vintage model, superseded by newer series

Since its 2022 launch, REC has released successors - Alpha Pure-RX (450-470 Wp) and Alpha Pure 2 - with higher unit power. Alpha Pure-R is no longer the flagship in REC's HJT lineup, though it remains in active production and fully warranty-supported.

Full bifacial gain depends on mounting conditions

Realized bifacial energy gain depends on ground albedo and mounting height - on typical pitched roofs with limited rear clearance, the additional rear-side yield may be marginal relative to the price premium of the technology.

Notes from the database
  • At 21.8% efficiency, this panel is on par with typical HJT 400-450W modules
  • At 217.2 W/m², this panel generates 4.4 W/m² less per unit area than HJT 400-450W median (221.6 W/m²)
  • At -0.24%/°C, hot weather performance is typical for HJT 400-450W panels
  • Weight of 21.5 kg (1.5 kg below HJT 400-450W median of 23.0 kg) allows easier transport and roof mounting
  • In the top 50% for efficiency among all HJT panels

Specifications

Open datasheet PDF
Nominal power (Pmax) 420 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 21.80 % Typical Segment median 22.20%
Vmpp · Impp 50.00 V · 8.40 A Operating point at max power
Voc · Isc 59.40 V · 8.88 A Sizes the string length
Max system voltage 1000 V Longer strings than 1000 V modules
Dimensions 1730×1118×30 mm · 1.93 m² of roof
Weight 21.5 kg Typical Typical · median 23.0 kg
Cells 80 · HJT Monocrystalline
Coefficient Pmax -0.240 %/°C Typical median -0.240 of its segment
Coefficient Voc · Isc -0.240 · 0.040 %/°C
NOCT 44 °C At 800 W/m², 20 °C ambient
Product warranty 25 years Hardware defects only
Performance warranty 25 years Weak bottom 8% · median 30 yrs
End-of-warranty output 92.0 % Equals 381 W guaranteed
Degradation 2.00 → 0.25 % First year, then annual

Simulations

Live - change any input
Lifetime output & value
30 years at 1200 kWh/kWp/year and €0.50 per kWh
Power in year 30
-
Lifetime energy
-
Energy value
-

Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.

Heat losses
-0.240 %/°C against a segment median of -0.240
-
Filter these
Size
Panel Power Eff. Temp. Weight Difference
REC REC420AA Pure-R 420 W 21.80% -0.240 21.5 kg You are here
JST-EDMH-(445-465)W-TD (465W class) 465 W 23.81% -0.300 20.5 kg Hotter, +2.0 pp, +5 yr warranty
LX-465M/182R-96+ GG 465 W 23.80% -0.260 23.5 kg +45 W, +2.0 pp, +5 yr warranty
SPR-MAX7-470 470 W 23.70% -0.270 21.1 kg +50 W, +1.9 pp, +15 yr warranty
AIKO-A470-MAH54Mb 470 W 23.60% -0.260 21.5 kg +50 W, +1.8 pp, +5 yr warranty
AIKO-A460-MAH54Mb 460 W 23.60% -0.290 20.5 kg Hotter, +1.8 pp, +5 yr warranty
HSM-BD54-LA470 470 W 23.60% -0.260 21.5 kg +50 W, +1.8 pp, +5 yr warranty
REC400AA PURE-R 400 W 20.70% -0.240 21.5 kg -20 W, -1.1 pp
REC410AA PURE-R 410 W 21.20% -0.240 21.5 kg -10 W, -0.6 pp
REC430AA PURE-R 430 W 22.30% -0.240 21.5 kg +10 W, +0.5 pp
LR7-54HJD-510M 510 W 25.00% -0.240 23.5 kg +90 W, +3.2 pp, +5 yr warranty
AIKO-A495-MCE54Mw 495 W 24.80% -0.260 21.0 kg +75 W, +3.0 pp, +5 yr warranty
LR7-54HJD-505M 505 W 24.70% -0.240 23.5 kg +85 W, +2.9 pp, +5 yr warranty
WST-505BKX54-A2 505 W 24.70% -0.260 25.0 kg +85 W, +2.9 pp, +5 yr warranty
AIKO-A490-MCE54Mw 490 W 24.50% -0.260 21.0 kg +70 W, +2.7 pp, +5 yr warranty
LR7-54HJD-500M 500 W 24.50% -0.240 23.5 kg +80 W, +2.7 pp, +5 yr warranty
CIPRO-TN9C54M-500W 500 W 24.50% -0.260 21.4 kg +80 W, +2.7 pp, +5 yr warranty

Found 56 panels of the same or similar size to this one, within ±10 mm. See them here Found 1955 panels of the same or similar size to this one, within ±25 mm. See them here Found 3413 panels of the same or similar size to this one, within ±50 mm. See them here Found 4011 panels of the same or similar size to this one, within ±100 mm. See them here

About the REC ALPHA® PURE-R series

6 answered

These answers cover the whole series. Where a figure differs, the specification above is this module's own.

What are the product and power output warranties for the REC Alpha Pure-R panels?
Under the REC ProTrust program - available when the system is installed by an REC Certified Solar Professional - you receive a 25-year product warranty and a 25-year power output warranty. After 25 years of operation the panel must retain at least 92% of its nameplate power, with a maximum warranted annual degradation of 0.25%, one of the lowest figures in the premium PV segment.
Do REC Alpha Pure-R panels lose significant power on hot summer days?
No. The HJT cell technology used in the REC Alpha Pure-R delivers a temperature coefficient of just -0.24%/°C for PMAX. By comparison, conventional PERC panels typically range from -0.34% to -0.40%/°C. In real-world terms this translates into noticeably higher energy yield during summer heat waves and better annual production figures in warm climates.
How does the REC Alpha Pure-R handle partial shading from a chimney or TV antenna?
The REC Alpha Pure-R module is internally split into four independent electrical sections, so shade falling on one portion of the panel limits losses only to that section - the remaining area continues operating at full power. Combined with the Twin Design architecture and the high efficiency of HJT cells, this series is especially well suited for rooftops with complex geometry or obstructions.
How does the HJT technology in the REC Alpha Pure-R differ from mainstream PERC, and is the premium worth it?
HJT cells stack a crystalline silicon wafer between thin amorphous silicon layers, achieving up to 22.3% module efficiency in the 430 Wp variant, along with a better temperature coefficient and lower long-term degradation than PERC. You get more energy from the same roof area over the full system lifetime. The premium is most justified when available mounting space is limited or an All-Black aesthetic is required.
The REC Alpha Pure-R is bifacial - does that make sense on a pitched residential roof?
Yes, though bifacial gains on a pitched roof are smaller than on a ground-mount system. The panel captures light reflected from the roofing surface or underlayment membrane, potentially adding a few percent of additional annual yield. The benefit is greatest on light-colored surfaces or where a structural gap exists between the panel and the roof. On a standard tile roof the bifacial design still improves the energy balance, though it is not the primary reason to choose this series.
Is REC a reliable manufacturer, and who backs the 25-year warranty?
REC Group is a Norwegian company with over 25 years of PV industry experience and is consistently ranked among Tier 1 manufacturers by Bloomberg NEF. The Alpha Pure-R panels are produced at ISO-certified facilities in Singapore. Tier 1 status reflects the financial strength needed to honor warranty obligations across a 25-year operational horizon, making REC a low-risk choice for long-term energy investments.
Add to compare