Strong in heat, short guarantee
Longi Solar ROOF 4 series was designed with the goal of maximizing roof space utilization and providing stable energy production in both domestic and commercial installations. Its key feature is the combination of monocrystalline PERC cells with half-cut technology, which in practice helps reduce power losses under everyday operating conditions - when partial shading, dirt, or uneven irradiance across roof sections occurs. The application of modern connection architecture in the module supports higher reliability and more predictable yields over the long term, which is appreciated by those planning long-term investments.
ROOF 4 series is also focused on easier installation design - the modules are compatible with popular inverters and optimizer solutions, making integration into typical rooftop systems less problematic. For investors, the all-black aesthetic is also important, especially in projects for single-family homes. Compared to many competitive rooftop modules, ROOF 4 emphasizes practical usability in real conditions rather than just catalog specifications.
Ranking
Signals from the data
Residential, commercial and shaded-installations.
Owners who want a long output guarantee.
Top 12% of the 500-700 W band, against a median of -0.300.
Bottom 11% of the 500-700 W band, against a median of 30 yrs.
The combination of monocrystalline PERC cells with half-cut technology meaningfully reduces power losses under partial shading, soiling, or uneven roof irradiance, while also lowering hot-spot risk due to reduced current per half-cell.
Longi Solar is a Tier-1, bankable manufacturer founded in 2000 and one of the world's largest silicon wafer suppliers, which simplifies project financing through banks and funds and reduces long-term service-continuity risk.
The series carries a 25-year product warranty plus a 25-year linear power warranty (typically ~84.8% power retention after 25 years), matching the standard offered by comparable PERC modules in this power class.
Module efficiency of 22.4-23.1% at 600-620 Wp is comparable to peer products such as HT-SAAE HT66-18X(ND)-F (23%) and Weran Solar LR7-72HTH (23%), placing the series mid-pack among the highest-power rooftop modules currently on the market.
The all-black variant is a key selling point for single-family home projects, and compatibility with popular inverters and power optimizers simplifies design for typical rooftop installations without extra component certification.
Unlike the comparable MY Solar G&A N-Type TOPCon Bifacial (620 Wp, 22.95%) in the same power and efficiency range, the ROOF 4 series lacks a dual-sided option, forgoing potential rear-side yield gains (typically a few to over ten percent depending on albedo and mounting) that competitors already offer.
PERC cells represent an older cell technology generation compared to N-type TOPCon, used by part of the competition in this power class (e.g., MY Solar). TOPCon typically has lower LID/LeTID degradation and a better power temperature coefficient (about -0.30%/°C vs. roughly -0.35%/°C typical for PERC in this series), translating into higher yield in hot climates and over long-term operation.
- At 22.4% efficiency, this panel is 0.6pp above typical database modules (median: 21.8%)
- Power density of 223.9 W/m² packs 5.8 W/m² more into the same footprint vs database median (218.1 W/m²)
- Temperature coefficient of -0.28%/°C matches the database median
- Weight of 31.0 kg is 4.5 kg above database median (26.5 kg) - verify structural support
- #4774 for efficiency, #1309 for temperature performance out of 14005 panels
Specifications
Simulations
Degradation from this panel's own datasheet figures. No inverter, soiling or shading losses.
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