SUNLU Filament Dryer Box 2026 S1 Plus Review: Solves Common Print Issues

The SUNLU S1 Plus features a compact design, accommodating standard 1kg filament spools. Owners note its size is convenient, fitting well alongside other printing equipment. While aesthetically pleasing to some, the unit's build quality receives mixed feedback. Several users describe the material as feeling inexpensive. The lid, though serviceable, is noted by one long-term user as feeling somewhat loose, raising durability concerns over time. The integrated rollers are effective, allowing spools to feed smoothly within the box, a crucial factor for direct printing setups. An internal fan is a key design alteration for this upgraded model, intended to improve drying times.

Initial setup for the S1 Plus generally involves powering the unit and understanding its controls. However, a consistent complaint among owners is the inadequacy of the provided instructions. Users frequently report a need to experiment with the two-button interface or seek external resources to grasp its functionality fully. Once the control logic for adjusting temperature and time is learned-a short press to change values, a long press to switch modes-the device operates straightforwardly. The LCD, though basic, clearly displays temperature, time, and humidity, providing useful feedback during operation. Many report an easy learning curve once the initial hurdle of deciphering the controls is overcome.

The primary function of the S1 Plus is filament drying, and in this regard, owner feedback is overwhelmingly positive. Users report significant improvements in print quality, citing reductions in stringing, clogs, and better bed adhesion, particularly with PLA, PETG, and TPU. Several mention successfully reviving heavily moisturized or very old filament. The fan-assisted drying is effective, with some users noting quick results even for very wet spools. The ability to print directly from the dryer is a highly valued feature, particularly for hygroscopic filaments like TPU; owners confirm it maintains filament dryness during printing, leading to more reliable output. However, one user noted the internal spool spin was not as smooth as a dedicated external spool holder, though it did not impede printing.

The SUNLU S1 Plus operates as a standalone device with no external software or app integration. Its interface is entirely hardware-based, relying on the two physical buttons and LCD screen. The display provides necessary information: current temperature, set temperature, remaining time, and humidity. While basic, this setup avoids potential software complexities and connectivity issues. Users appreciate the simplicity and direct control, even if the initial learning curve for button presses takes some adjustment. The absence of additional software components aligns with its function as a dedicated filament drying unit.

For its price point, generally found in the sub-$50 range, the SUNLU S1 Plus delivers strong value according to its user base. Owners frequently describe it as a cost-effective solution that effectively addresses prevalent 3D printing issues caused by wet filament. The device's reliability in drying filament and enhancing print quality is a recurring theme in positive feedback. While some concerns exist regarding the perceived build quality and an initial learning curve for controls, the consistent results in preventing print failures position it as a worthwhile investment for many. Long-term reliability is suggested by several owners purchasing multiple units or reporting extended usage without significant issues, though one user did experience an intermittent problem resolved by SUNLU customer service.