REC REC640AA PRO M vs REC REC620AA Pro MG
VS
The verdict
REC640AA PRO M leads on the differences that matter
The largest is module efficiency: 0.70 pp more efficient. 12 of 19 comparable parameters are identical.
See all 7 differencesHow alike are they
12
of 19 comparable
parameters are identical
parameters are identical
identical
differs
01
7 of 19 parameters
What actually differs
Parameter
REC640AA PRO M
REC620AA Pro MG
Difference
Module efficiency
22.50 %
21.80 %
0.70 pp more efficient
Performance warranty
25 yrs
30 yrs
5 yrs longer
Weight
32.5 kg
36.8 kg
4.3 kg lighter
Weight per kWp
50.8 kg/kWp
59.4 kg/kWp
8.6 kg/kWp lighter
Product warranty
20 yrs
30 yrs
10 yrs longer
Power density
225.5 Wp/m²
218.4 Wp/m²
7.0 Wp/m² higher
Rated power
640 Wp
620 Wp
20 W more power
02
What it means on a roof
Thirty years of production
Each panel's own declared degradation curve, at 1,200 kWh/kWp a year
Same temp coeff. for both panels (-0.240 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
REC640AA PRO M
21,744 kWh
REC620AA Pro MG
21,065 kWh
Lifetime gap
679 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario
REC640AA PRO M
REC620AA Pro MG
Standard test conditions
25 °C
100.0% of rated power
640 W
620 W
Cool, bright day
40 °C
96.4% of rated power
617 W
598 W
Typical summer roof
55 °C
92.8% of rated power
594 W
575 W
Hot roof
70 °C
89.2% of rated power
571 W
553 W
03
Full specification
Parameter
REC640AA PRO M
REC620AA Pro MG
Difference
Power and efficiency
Rated power
640 Wp
620 Wp
+20 W for REC640AA PRO M
Module efficiency
22.50 %
21.80 %
+0.70 pp for REC640AA PRO M
Power density
225.5 Wp/m²
218.4 Wp/m²
+7.0 Wp/m² for REC640AA PRO M
Open-circuit voltage
44.60 V
44.60 V
Same
Voltage at max power
37.10 V
36.60 V
Effectively the same
Short-circuit current
17.93 A
17.67 A
Effectively the same
Current at max power
17.26 A
16.94 A
Effectively the same
Temperature
Temperature coefficient
-0.240 %/°C
-0.240 %/°C
Same
Mechanical
Dimensions
2175x1305x30 mm
2175x1305x30 mm
Same
Module area
2.838 m²
2.838 m²
Same
Weight
32.5 kg
36.8 kg
-4.3 kg for REC640AA PRO M
Weight per kWp
50.8 kg/kWp
59.4 kg/kWp
-8.6 kg/kWp for REC640AA PRO M
Warranty and degradation
Product warranty
20 yrs
30 yrs
+10 yrs for REC620AA Pro MG
Performance warranty
25 yrs
30 yrs
+5 yrs for REC620AA Pro MG
Annual degradation
0.25 %/yr
0.25 %/yr
Same
Technology
Cell technology
HJT
HJT
Same
Cell type
Monocrystalline
Monocrystalline
Same
Cell count
120
120
Same
Bifacial
Yes
Yes
Same
04
14,005 panels
Against the whole database
Efficiency
#4,222
vs
#7,022
REC640AA PRO M leads by 2,800 places
Power density
#3,889
vs
#6,952
REC640AA PRO M leads by 3,063 places
Heat behaviour
#13
vs
#13
Tied - the same position in the database
Weight
#4,196
vs
#12,117
REC640AA PRO M leads by 7,921 places
Warranty
#9,798
vs
#21
REC620AA Pro MG leads by 9,777 places
Overall
#1,949
vs
#1,182
REC620AA Pro MG leads by 767 places
05
Open the full database
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06
Written summary
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07
Questions about this pairing
Which panel is better: REC REC640AA PRO M or REC REC620AA Pro MG?
According to our database: REC REC640AA PRO M has higher module efficiency (22.50% vs 21.80%). See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of REC REC640AA PRO M and REC REC620AA Pro MG?
REC REC640AA PRO M has a module efficiency of 22.50%, while REC REC620AA Pro MG is 21.80%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does REC REC640AA PRO M use vs REC REC620AA Pro MG?
REC REC640AA PRO M uses HJT cells; REC REC620AA Pro MG uses HJT. Modern n-type technologies (TOPCon, HJT, BC) typically deliver higher efficiency and lower degradation compared to older PERC (p-type) cells.
What is the warranty on REC REC640AA PRO M and REC REC620AA Pro MG?
REC REC640AA PRO M has a 25 years power warranty; REC REC620AA Pro MG has a 30 years power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80-87%). Product (materials) warranties are usually shorter.
Are REC REC640AA PRO M and REC REC620AA Pro MG bifacial panels?
Both REC REC640AA PRO M and REC REC620AA Pro MG are bifacial - they capture reflected light from the ground, which can add 5-15% more annual energy on ground-mount or elevated rooftop installations with a light surface beneath.
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Every figure here is from the manufacturers' own datasheets - a dash means the value is not published, never an estimate. The thirty-year projection and the temperature scenarios are calculations from those figures, and each states its assumption above.