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Viessmann M405WK
Viessmann Brand review

M405WK

405 Wp PERC
ComparePV verdict

Strong in heat, no clear weak spot

Rank 11,663 of 14,005
Compare panels Datasheet PDF
Power (Wp)
405
Typical for its class
Efficiency (%)
20.66
Typical · median 20.60%
Density (Wp/m²)
206.7
Typical · median 206.2
Temp (%/°C)
-0.340
Strong · top 24%
Weight (kg)
22.0
Typical · median 22.0 kg
Warranty (yrs)
25
Typical · median 25 yrs

Vitovolt 300 is an advanced line of photovoltaic modules that combines high efficiency with exceptional durability, meeting the needs of investors seeking full energy security. This series utilizes innovative shingled cell technology, which eliminates gaps between cells, increasing the active surface area and performance in difficult lighting conditions. Thanks to this solution, the panels handle shading much better than standard products, maintaining high electricity production even when the module surface is partially covered. These products solve the problem of power degradation over time, offering a 25-year performance warranty and excellent resistance to aggressive external factors, such as ammonia or salt spray. It is an ideal choice for modern farms, single-family homes, and buildings in demanding coastal areas. Compared to the competition, Vitovolt 300 stands out with high mechanical strength of 6000 Pa, which guarantees structural stability even during extreme snowfall. The series provides an elegant design with a black frame, which harmoniously blends with any roof architecture. It is a complete system for those who value European engineering standards, offering positive power tolerance, which translates into real yields above nominal values and a faster return on investment in the variable Polish climate.

Ranking

954 panels in the segment PERC 400-450 W
Metric This panel Median Position in segment Overall rank
Module efficiency 20.66% 20.60% Typical 11,009
Power density 206.7 206.2 Typical 10,965
Temperature coefficient -0.340 -0.350 Strong · top 24% 8,778
Weight per kWp 54.3 53.0 Typical 8,586
Performance warranty 25 yrs 25 yrs Typical 9,798
Colour key Strong - top 25% Typical - middle 50% Weak - bottom 25%

Signals from the data

1 positive · 0 caution
Best for

Residential, shaded-installations and cold-climate.

Strengths
-0.340 %/°C temperature coefficient

Top 24% of the PERC 400-450 W segment, against a median of -0.350.

Notes from the database
  • Efficiency of 20.7% matches the PERC 400-450W median
  • At 206.7 W/m² power density, roof space requirements are typical for PERC 400-450W panels
  • At -0.34%/°C, hot weather performance is typical for PERC 400-450W panels
  • #11009 for efficiency, #8778 for temperature performance out of 14005 panels

Specifications

Open datasheet PDF
Nominal power (Pmax) 405 Wp Nameplate at 1000 W/m², 25 °C
Module efficiency 20.66 % Typical Segment median 20.60%
Vmpp · Impp 38.70 V · 10.47 A Operating point at max power
Voc · Isc 46.50 V · 11.02 A Sizes the string length
Max system voltage 1500 V Longer strings than 1000 V modules
Dimensions 1719×1140×30 mm · 1.96 m² of roof
Weight 22.0 kg Typical Typical · median 22.0 kg
Coefficient Pmax -0.340 %/°C Strong top 24% of its segment
Coefficient Voc · Isc -0.270 · 0.040 %/°C
NOCT 42 °C At 800 W/m², 20 °C ambient
Product warranty 15 years Hardware defects only
Performance warranty 25 years Typical median 25 yrs · median 25 yrs
End-of-warranty output 84.8 % Equals 333 W guaranteed
Degradation 3.00 % First year

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
-0.340 %/°C against a segment median of -0.350
-
Filter these
Size
Panel Power Eff. Temp. Weight Difference
Viessmann M405WK 405 W 20.66% -0.340 22.0 kg You are here
AIKO-455-MAH54Db 455 W 23.30% -0.260 24.0 kg +50 W, cooler, +2.6 pp
LR5-54HTH-455M 455 W 23.30% -0.290 20.8 kg +50 W, cooler, +2.6 pp
YL455CF54 e/2 455 W 23.30% -0.290 20.3 kg +50 W, cooler, +2.6 pp
ESM-455T 455 W 23.30% -0.310 21.0 kg +50 W, +2.6 pp, +5 yr warranty
SE5-54HBC-455W 455 W 23.30% -0.290 20.8 kg +50 W, cooler, +2.6 pp
JST-EDMH-(445-465)W-TD (455W class) 455 W 23.30% -0.300 20.5 kg +50 W, +2.6 pp, +5 yr warranty
LX-455M/182R-96+ GG 455 W 23.30% -0.260 23.5 kg +50 W, cooler, +2.6 pp
M395WK 395 W 20.15% -0.340 22.0 kg -10 W, -0.5 pp
M400WE 400 W 20.40% -0.340 22.0 kg -0.3 pp
LR7-54HJD-510M 510 W 25.00% -0.240 23.5 kg +105 W, cooler, +4.3 pp
AIKO-A495-MCE54Mw 495 W 24.80% -0.260 21.0 kg +90 W, cooler, +4.1 pp
LR7-54HJD-505M 505 W 24.70% -0.240 23.5 kg +100 W, cooler, +4.0 pp
AIKO-A490-MCE54Mw 490 W 24.50% -0.260 21.0 kg +85 W, cooler, +3.8 pp
LR7-54HJD-500M 500 W 24.50% -0.240 23.5 kg +95 W, cooler, +3.8 pp
CIPRO-TN9C54M-500W 500 W 24.50% -0.260 21.4 kg +95 W, cooler, +3.8 pp

Found 1746 panels of the same or similar size to this one, within ±10 mm. See them here Found 1902 panels of the same or similar size to this one, within ±25 mm. See them here Found 3386 panels of the same or similar size to this one, within ±50 mm. See them here Found 3817 panels of the same or similar size to this one, within ±100 mm. See them here

Common questions

6 answered
What is shingled cell technology used in Vitovolt 300 and is it worth choosing?
Shingled technology connects strips of PERC cells with no gaps between them, increasing the module's active surface area and reducing losses at cell junctions. In practice, the panel handles partial shading - from a chimney or antenna, for example - better than modules with conventional cell layouts, maintaining higher power output. It also gives the surface a more uniform look, without visible busbar grids.
What warranty comes with Viessmann Vitovolt 300 modules?
Vitovolt 300 comes with a 15-year product warranty covering material and workmanship defects, plus a 25-year linear power warranty guaranteeing a minimum performance level over the module's service life. This warranty structure gives investors confidence that the installation will keep producing at a high level throughout the typical loan repayment or depreciation period used in most Polish PV subsidy programs.
Are Vitovolt 300 panels suitable for a farm building roof or a coastal location?
Yes, Vitovolt 300 modules are tested for resistance to ammonia and salt mist, making them a solid choice for farm buildings (barns, poultry houses) and structures near the sea, where standard panels can corrode faster. The black frame and clean design also blend well with both agricultural roofs and single-family homes in more demanding environmental conditions.
What is the maximum power output of Vitovolt 300 panels, and how many are needed for a 5 kWp system?
Vitovolt 300 modules reach a maximum power output of up to 405 Wp. For a residential 5 kWp system, that means roughly 12-13 panels, depending on the exact inverter configuration and available roof space. Thanks to the positive power tolerance, individual modules often slightly exceed their rated output in practice, resulting in somewhat higher yields than theoretical calculations alone would suggest.
Can Vitovolt 300 panels handle heavy snow loads and strong wind?
Yes, the series offers high mechanical load resistance of up to 6000 Pa, well above typical requirements for the Polish climate. This construction allows the panels to safely handle heavy snow accumulation on the roof as well as strong wind gusts, without risk of glass cracking or frame deformation - a key advantage for buildings in regions with variable weather.
Are Viessmann Vitovolt 300 panels bifacial?
No, Vitovolt 300 modules are mono-facial, using shingled PERC cells enclosed in a conventional, non-transparent backsheet structure. This means they generate power only from light hitting the front side of the panel, unlike bifacial modules that also capture light reflected off the ground. For typical sloped roofs, this is a fully sufficient and more cost-effective solution.
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