--- title: "Hiwatt Solar HW-M6/120H-365 365W Solar Panel - Specs & Review | ComparePV" description: "Hiwatt Solar HW-M6/120H-365 365W solar panel. Specs: 19.70% efficiency, Monocrystalline cells, dimensions, warranty and temperature coefficient." source: "https://comparepv.com/panel/hiwatt-solar-hw-m6-120h-365" updated: 2026-09-11 --- # Hiwatt Solar HW-M6/120H-365 Strong in heat, no clear weak spot 579 panels in the segment PERC 350-400 W ## Identity - **Manufacturer:** Hiwatt Solar - **Model:** HW-M6/120H-365 - **Series:** HW-M6/120H(350-370) - **Rated power:** 365 W - **Cell technology:** PERC ## How it compares Compared against segment PERC 350-400 W (579 panels). | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Power (Wp) | 365 W | 380 W | Weak - bottom 20% | | | Module efficiency | 19.70% | 19.90% | Typical | 12,511 | | Power density | 200.4 | 199.0 | Typical | 12,147 | | Temperature coefficient | -0.340 | -0.350 | Strong - top 15% | 8,778 | | Weight (kg) | 20.5 kg | 21.4 kg | Typical | | | Performance warranty | 25 yrs | 25 yrs | Typical | 9,798 | ### Full peer table | Measure | This panel | Segment median | Standing | Rank | | --- | --- | --- | --- | --- | | Module efficiency | 19.70% | 19.90% | Typical | 12,511 | | Power density | 200.4 | 199.0 | Typical | 12,147 | | Temperature coefficient | -0.340 | -0.350 | Strong - top 15% | 8,778 | | Weight per kWp | 56.2 | 55.8 | Typical | 10,443 | | Performance warranty | 25 yrs | 25 yrs | Typical | 9,798 | ### Strengths - **-0.340 %/°C temperature coefficient** - Top 15% of the PERC 350-400 W segment, against a median of -0.350. - **Best for:** Residential, commercial and shaded-installations. ## Specification ### Electrical - **Rated power (Pmax):** 365 W - **Efficiency:** 19.70 % - **Voltage at Pmax (Vmp):** 33.90 V - **Current at Pmax (Imp):** 10.78 A - **Open-circuit voltage (Voc):** 40.60 V - **Short-circuit current (Isc):** 11.47 A - **Max system voltage:** 1500 V ### Temperature - **Temperature coefficient of Pmax:** -0.340 %/degC - **Temperature coefficient of Voc:** -0.250 %/degC - **Temperature coefficient of Isc:** 0.040 %/degC - **NOCT:** 43 degC ### Cell and construction - **Cell type:** Monocrystalline - **Cell technology:** PERC - **Cell count:** 120 ### Physical - **Length:** 1755 mm - **Width:** 1038 mm - **Thickness:** 35 mm - **Weight:** 20.5 kg - **Area:** 1.82 m2 - **Power density:** 200.4 Wp/m2 ### Warranty and degradation - **Product warranty:** 12 years - **Performance warranty:** 25 years - **Output guaranteed at end of warranty:** 84.8 % - **First-year degradation:** 2.00 % - **Annual degradation:** 0.55 % - **Output after 30 years:** 299 W ## Rank in the whole catalogue | Measure | Position | | --- | --- | | Efficiency | 12511 of 14005 | | Power density | 12147 of 14005 | | Temperature coefficient | 8778 of 14005 | | Weight | 10443 of 14005 | | Warranty | 9798 of 14005 | ## Pros - **Half-Cut + Multi-Busbar M6 cells** - Half-cut cell architecture on M6 (166 mm) wafers combined with a Multi-Busbar layout reduces series resistance and partial-shading losses by up to 30% compared to conventional full-cell modules. This translates into higher annual energy yield on typical Polish rooftops with shading obstacles such as chimneys and dormers. - **Up to 20% efficiency – segment leader** - Peak module efficiency of 20.0% places the series above the peer-comparable Solitek SOLID Bifacial (19.57%) and nearly on par with Solarwatt Panel vision GM 3.0 style (19.9%) at the same 370 Wp power level. On a 20 m² roof, this gain over a previous-generation PERC module (≈18.5%) amounts to roughly 30 Wp extra with no change in module count. - **25-year linear power warranty** - The manufacturer provides a 25-year linear power output warranty, confirmed in the ENF Solar database for this series. At a typical PERC half-cut annual degradation rate of ≈0.55%/year, the module retains approximately 86.7% of nominal power after 25 years — an acceptable threshold for residential LCOE calculations. - **Low LID and anti-reflective coating** - PERC half-cut technology on M6 wafers exhibits lower Light Induced Degradation (LID) than older Al-BSF full-cell modules, typically below 1% in the first 1,000 operating hours. The tempered-glass anti-reflective coating improves light absorption at incidence angles above 60°, which is particularly relevant during the low-sun autumn and winter months in Poland. - **5 power variants (350–370 Wp)** - The series covers five power steps across a 20 Wp range, making it straightforward to optimize module count against inverter MPPT window voltage limits without mixing different series in a single string. ## Cons - **Discontinued product line** - The discontinued flag in the manufacturer's database means active production of the HW-M6/120H has ceased. Replacing a mechanically damaged module in an existing system may be impossible without redesigning the string, because matching frame color, Wp rating, and electrical parameters to legacy units is no longer guaranteed. This is especially problematic for systems above 10 kWp, where replacing only a subset of modules alters the string IV curve. - **Not a BNEF Tier-1 bankable manufacturer** - Hiwatt Solar does not appear on BloombergNEF's bankable Tier-1 list (confirmed absent from Q2 2025 and Q4 2025 editions). For commercial and utility-scale projects above 50 kWp seeking bank financing or leasing, the absence of Tier-1 status leads to stricter due diligence requirements or outright financing refusals by some institutions. - **Monofacial only – no bifacial gain** - The series is monofacial, while the direct peer Solitek SOLID Bifacial (370 Wp, 19.57% efficiency) offers rear-side generation of 5–25% depending on ground albedo. On ground-mount or white-membrane roof installations, this represents a meaningful loss of annual production at no additional material cost. - **12-year product warranty only** - The 12-year workmanship warranty is half the length of Panasonic EVERVOLT Black Series (25 years) and a fraction of Solarwatt Panel vision GM 3.0 (30-year combined warranty). Over a standard 25-year system lifetime, the last 13 years fall outside product warranty coverage, shifting the financial risk of manufacturing defects — delamination, cell corrosion — entirely to the system owner. - **Efficiency below premium segment** - Peak efficiency of 20.0% lags 1.2 percentage points behind the Panasonic EVERVOLT 370K (21.2%), which operates in the same nominal power class. On a constrained roof area of 30 m², this difference means that achieving 5.55 kWp requires 15 HW-M6/120H modules (at 370 Wp each), whereas 14 Panasonic units suffice — a relevant constraint for mansard roofs and garages. ## About this series The Hiwatt Solar HW-M6/120H(350-370) panel series is a modern solution based on **Half-Cut cell technology**, which significantly minimizes energy losses resulting from partial shading or module soiling. Thanks to the use of larger M6 silicon wafers and a **Multi-Busbar system**, these panels offer higher power density while maintaining optimal dimensions, making them an ideal choice for roofs with limited space. This design effectively reduces mechanical stress and the risk of micro-cracks, which directly translates into **exceptional mechanical durability** and long-term yield stability. They solve the problem of efficiency drops at high temperatures thanks to a favorable temperature coefficient, which sets them apart from standard modules available on the market. This series is dedicated to both individual prosumers and commercial projects looking for the optimal balance between price and innovation. The use of an **anti-reflective coating** allows for better light absorption even at a low angle of incidence of sunlight. Compared to the competition, the HW-M6/120H is characterized by a very low level of initial LID degradation, providing users with the certainty that their investment in photovoltaics will maintain high efficiency for decades, regardless of the harsh weather conditions typical of the Polish climate. ## Notable figures - At 19.7% efficiency, this panel is on par with typical \*\*PERC 0-400W\*\* modules - 200.4 W/m² power density - 6.0 W/m² more than \*\*PERC 0-400W\*\* median (194.4 W/m²), more power per roof area - Temperature coefficient of -0.34%/°C matches the \*\*PERC 0-400W\*\* median - #12511 for efficiency, #8778 for temperature performance out of 14005 panels ## Questions ### Is the Hiwatt Solar HW-M6/120H(350-370) series still available for purchase? The HW-M6/120H(350-370) series has been discontinued and is no longer available through regular distribution channels. Limited stock may still exist with select distributors. If you need a current alternative, consider newer Hiwatt Solar series or comparable PERC half-cut modules from other manufacturers with similar power output and specifications. ### What warranty does the Hiwatt Solar HW-M6/120H series come with? The HW-M6/120H series comes with a 12-year product warranty covering material and workmanship defects, and a 25-year linear power output warranty ensuring the panels retain a specified performance level over a quarter century. Note that Hiwatt Solar is not classified as a Tier 1 manufacturer, which is worth considering when evaluating long-term warranty support reliability. ### What is half-cut PERC technology in the HW-M6/120H panels and is it worth it? In the HW-M6/120H, PERC cells are laser-cut in half to produce 120 cells instead of the standard 60. This reduces resistive losses, lowers operating current, and significantly improves performance under partial shading from chimneys or antennas. The PERC layer reflects unabsorbed photons back into the cell, boosting conversion efficiency. It is a proven technology, particularly beneficial on roofs with shading obstacles. ### Are the Hiwatt Solar HW-M6/120H panels a good fit for a partially shaded roof with a chimney or dormer? Yes, the half-cut design with 120 cells greatly improves module performance under partial shading. Splitting each cell means a shaded section does not fully suppress output from the unshaded half. Keep in mind that the HW-M6/120H is a monofacial module, not bifacial, and best results are achieved when paired with an inverter featuring a well-tuned MPPT algorithm. ### What is the peak power of the HW-M6/120H panels and how does that work for a typical residential system? The HW-M6/120H series ranges from 350 to 370 Wp, with the top variant rated at 370 Wp. A typical 6 kWp residential system would require approximately 16 to 17 panels. The larger M6 silicon wafers combined with a multi-busbar design deliver this power output while keeping the module footprint compact, making it practical for roofs with limited usable area. ### How do HW-M6/120H panels perform in high summer temperatures typical of the Polish climate? The HW-M6/120H series features a favorable temperature coefficient, meaning it loses less power on hot days compared to standard polycrystalline modules. The anti-reflective coating improves light absorption at low irradiance angles, such as during early morning hours or in autumn. Additionally, low initial LID degradation ensures the panel retains its rated power long after the first weeks of operation. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/HW-M6120H-350-370-4a509c795152.pdf) ## Alternatives | Panel | Power | How it differs | | --- | --- | --- | | [JA Solar NS-330MH-80](https://comparepv.com/panel/ja-solar-ns-330mh-80) | 330 W | Cooler, lighter, +3.4 pp | | [PolyCrown Solar Tech NS-330MH-80](https://comparepv.com/panel/polycrown-solar-tech-ns-330mh-80) | 330 W | Cooler, lighter, +3.4 pp | | [Gamko New Energy GKA210M320W](https://comparepv.com/panel/gamko-new-energy-gka210m320w) | 320 W | -45 W, +3.3 pp, +5 yr warranty | | [Gamko New Energy GKA210M340W](https://comparepv.com/panel/gamko-new-energy-gka210m340w) | 340 W | Lighter, +3.3 pp, +5 yr warranty | | [Gamko New Energy GKA210M360W](https://comparepv.com/panel/gamko-new-energy-gka210m360w) | 360 W | Lighter, +3.3 pp, +5 yr warranty | | [Gamko New Energy GKA210M380W (1/4\*4\*38)](https://comparepv.com/panel/gamko-new-energy-gka210m380w-1-4-4-38) | 380 W | Lighter, +3.3 pp, +5 yr warranty | | [Gamko New Energy GKA210M400W (1/2\*4\*20)](https://comparepv.com/panel/gamko-new-energy-gka210m400w-1-2-4-20) | 400 W | +35 W, +3.3 pp, +5 yr warranty | | [Gamko New Energy GKA210M400W (1/4\*4\*40)](https://comparepv.com/panel/gamko-new-energy-gka210m400w-1-4-4-40) | 400 W | +35 W, +3.3 pp, +5 yr warranty | | [Gamko New Energy GKA210M380W (1/2\*4\*19)](https://comparepv.com/panel/gamko-new-energy-gka210m380w-1-2-4-19) | 380 W | Lighter, +3.3 pp, +5 yr warranty | | [Maxeon SPR-MAX3-400-COM](https://comparepv.com/panel/maxeon-spr-max3-400-com) | 400 W | Cooler, +2.9 pp, +15 yr warranty | | [Hiwatt Solar HW-M6/120H-350](https://comparepv.com/panel/hiwatt-solar-hw-m6-120h-350) | 350 W | -15 W, -0.8 pp | | [Hiwatt Solar HW-M6/120H-355](https://comparepv.com/panel/hiwatt-solar-hw-m6-120h-355) | 355 W | -10 W, -0.5 pp | | [Hiwatt Solar HW-M6/120H-360](https://comparepv.com/panel/hiwatt-solar-hw-m6-120h-360) | 360 W | Very close match | | [Hiwatt Solar HW-M6/120H-370](https://comparepv.com/panel/hiwatt-solar-hw-m6-120h-370) | 370 W | +0.3 pp | | [Longi Solar LR7-54HJD-510M](https://comparepv.com/panel/longi-lr7-54hjd-510m) | 510 W | +145 W, cooler, +5.3 pp | | [AIKO AIKO-A495-MCE54Mw](https://comparepv.com/panel/aiko-aiko-a495-mce54mw) | 495 W | +130 W, cooler, +5.1 pp | --- Source: https://comparepv.com/panel/hiwatt-solar-hw-m6-120h-365 Not in this file, on the page: a thirty-year output simulator and alternatives filtered by how closely they match these dimensions.