SUNLU Filament Dryer S1 Plus - Dry While You Print for Better Results

In this review the SUNLU Filament Dryer S1 Plus is judged as a practical solution for hobbyists and small workshops that struggle with damp filament. The dryer is best for users who want to reduce common print defects caused by moisture - like stringing, clogging, poor adhesion and layer shifts - because it can dry spools while feeding a printer. It is straightforward to use, offers adjustable temperature and time controls, and aims to keep filament dry during printing so models come out more reliable.

Key Features

• Built-in circulation fan: Maintains even drying inside the enclosure so filament is dried consistently rather than only at the spool surface.
• Adjustable temperature 35C-55C: Lets the user set heat to suit different materials and ambient humidity for safer, tailored drying.
• Timer 0-24 hours: Offers flexible drying schedules with a default continuous 6 hour mode that fits normal filament drying needs.
• Compatibility with common spool sizes: Fits standard spools up to 210 x 85(H) mm and works with 1.75 mm, 2.85 mm and 3.00 mm filament diameters.
• Print-while-drying design: Two internal rollers allow filament to unspool directly from the dryer for simultaneous drying and printing.
• Quiet operation and clear display: The large 2 in LCD and ultra-quiet design (under 10 dB) keep monitoring easy without disturbing the workspace.

Who It's For

The SUNLU S1 Plus suits makers, resin and FDM hobbyists, and small lab users who frequently print with hygroscopic materials or live in humid environments and need a compact dryer that can operate during a print. It is especially useful for users who want a dedicated unit rather than improvised solutions, and for those printing flexible filaments like TPU that show clear quality gains when dry.

It may be less appropriate for industrial users who need very large spool capacity or higher maximum temperatures for specialty materials, and those who require integrated vacuum or desiccant systems for long-term storage should look at larger, purpose-built archival solutions.

Pros & Cons

Pros

• Effectively reduces moisture-related print issues, improving print quality for common filaments.
• Offers user control with a clear LCD for both temperature and time settings.
• Works with most mainstream spool brands and three standard diameters for wide compatibility.
• Quiet operation means it can run in a home or shared workspace without distraction.

Cons

• Some users report mixed feedback on maximum heat performance, so it may not reach desired temperatures for every situation.
• Capacity is limited to smaller spools (210 x 85 mm), so very large industrial spools will not fit.

Specifications

Our Verdict

The SUNLU Filament Dryer S1 Plus is a practical, value-oriented accessory for hobbyists and small shops that want more reliable prints from standard filaments. With adjustable temperature and timing, compatibility with common spool sizes and quiet operation, it removes much of the headache caused by damp filament; professionals who need larger capacity or higher temperatures should consider more heavy-duty options.

Frequently Asked Questions

Can I print while the filament is in the dryer?
Yes. The internal rollers are designed so filament can unspool while drying and feed your printer directly.

What filament diameters are supported?
The unit supports the three common diameters: 1.75 mm, 2.85 mm and 3.00 mm.

How long should I dry typical filament?
Under normal conditions 3-6 hours is generally sufficient, and the S1 Plus lets you set time anywhere from 0 to 24 hours if longer drying is needed.