SUNLU S2 vs S4: Which Filament Dryer Should You Buy in 2026?
A single-spool desk dryer against a four-spool workstation: what the specs say, what each costs, and who each one suits.
Checked 2026-11-04 Prices and availability checked on 2026-11-04; they may change.See SUNLU dryers
SUNLU S2 vs S4 at a glance
| Spec | FilaDryer S2 | FilaDryer S4 |
|---|---|---|
| Capacity | One 1 kg spool (max Ø210 × 85 mm) | Four 1 kg spools (chamber 450 × 210 × 211 mm) |
| Temperature range | 35–70 °C | Up to 70 °C |
| Power | About 48 W | Rated 320 W (PTC heater) |
| Heating method | 360° surround heating plus fan | PTC heater with circulation fans, ±3 °C balance |
| Humidity control | Timer and temperature presets | Auto mode: target 30–50% RH, stops at 25% |
| Print while drying | Yes, via PTFE tube | Yes, outlets for up to 4 printers |
| Footprint | 265 × 274 × 118 mm, 1.19 kg | 458 × 218 × 312 mm, ~4.8 kg |
| Warranty (S4 page) | S4: 1 year, per SUNLU's product page | |
| Price on SUNLU US store | $45.99 (was $79.99) | $116.99 (was $139.99) |
Specs and prices come from SUNLU's own store pages and its S2 vs S4 vs E2 guide. SUNLU's pages and third-party sites quote slightly different S4 heater figures (300 W vs 320–350 W); we use the rated 320 W from the product page.
SUNLU S2 vs S4: which one fits your printing?
SUNLU FilaDryer S2
- One 1 kg spool, 35–70 °C
- Touchscreen with one-key presets
- Listed at under 10 dB in operation
- Compact, desk-friendly
SUNLU FilaDryer S4
- Four 1 kg spools at once
- Reaches 50 °C in about 30 minutes (SUNLU)
- Auto humidity mode
- Feeds up to 4 printers
Pick the S2 if...
- you have one printer and keep one or two rolls in rotation;
- desk space and electricity use matter;
- you want a first dryer under $50 for PLA, PETG or TPU.
Pick the S4 if...
- you run an AMS-style multi-colour setup or more than one printer;
- you want a dry-storage box that also dries, not a single-spool unit;
- you accept a bigger footprint and a much higher power rating.
Is a filament dryer worth it?
Moisture-prone filaments such as PETG, TPU and nylon can absorb water from the air, and SUNLU lists bubbling, stringing and weak layers as typical symptoms. A dryer that keeps heating while the spool feeds the printer addresses this in one step. Both models support print-while-drying through PTFE tubing. If you only print PLA occasionally in a dry room, a dryer is a convenience rather than a necessity.
What about the S4 Pro and E2?
If 70 °C is not enough, SUNLU also sells the S4 Pro (dual-zone control, up to 85 °C, annealing mode, listed at $139.99 on the US store) and the E2 (up to 110 °C, listed at $249.99). SUNLU positions both for nylon, PC and carbon-fibre filaments.
Strengths on paper / Watch-outs
Strengths on paper
- S2: low price, tiny footprint, quiet rating
- S4: four-spool capacity and multi-printer outlets
- Both: print-while-drying and 1.75/2.85/3.0 mm support (S4 page)
Watch-outs
- Both cap at 70 °C, so no engineering-grade drying
- S2 holds only one spool
- S4 is large and rated at 320 W
- Prices vary by region and bundle
SUNLU S2 vs S4: FAQ
Is the SUNLU S4 worth it over the S2?
Only if you need to dry or store several spools at once. For one printer the S2 does the core job for less than half the price.
Can the S2 or S4 dry nylon?
Both stop at 70 °C. SUNLU points nylon, PC and similar materials to the S4 Pro or E2.
Can I print while the filament is drying?
Yes. SUNLU lists PTFE tube feed-through on both models so the spool keeps drying as it feeds.
How many spools does the S4 hold?
Four 1 kg spools, in a 450 × 210 × 211 mm chamber according to SUNLU.
Related on PickNexo
- SUNLU PLA vs PLA+ vs PLA+ 2.0: which filament to buy
- SUNLU store review: filament and dryers
- QIDI Q2 vs Plus 4 enclosed 3D printers
- More PickNexo buying guides
Sources
- SUNLU FilaDryer S4 product page
- SUNLU S2 filament dryer product page
- SUNLU: S2 vs S4 vs E2 comparison
- SUNLU FilaDryer S4 Pro product page
PickNexo has not tested these products hands-on; this article summarises official information and reputable reports. Some links are affiliate links, which may earn us a commission at no extra cost to you. Affiliate disclosure.