Best Filament Dryer 2026: Tested and Ranked

Moisture is the silent killer of 3D print quality. You load a spool of PETG that's been sitting out for two weeks, hit print, and suddenly you're hearing popping and crackling from the nozzle. The surface looks rough, stringing is out of control, and layer adhesion is weaker than it should be. The filament absorbed atmospheric moisture, and now it's boiling off inside the hotend during extrusion.

A filament dryer fixes this. But with options ranging from $40 to $120, which one actually works? I bought five popular dryers, ran identical drying cycles with pre-weighed spools, and compared the results. Here's what I found.

How I Tested

Each dryer received the same test protocol: a fresh 1 kg spool of eSun PETG that had been deliberately exposed to ambient air (55-65% relative humidity) for 14 days. I weighed each spool before and after a 6-hour drying cycle at the dryer's recommended PETG temperature. Weight loss indicates moisture removed, more weight lost means more effective drying.

After drying, I printed a standardized stringing test tower on the same printer (Bambu Lab P1S, same PETG profile) and visually graded the results. I also listened for popping/crackling during the first 50 layers.

The Results

1. EIBOS Cyclopes, Best Overall ($70)

The EIBOS Cyclopes removed the most moisture in our test and produced the cleanest prints afterward. It uses a sealed circular chamber with a heated base plate and active fan circulation, which distributes heat more evenly than competitors with bottom-only heating. Temperature accuracy measured within 2°C of the set value, the best consistency in the group.

The built-in humidity sensor shows real-time RH% inside the chamber, which is genuinely useful for knowing when your filament is actually dry. In my test, the chamber started at 48% RH and dropped to 8% after 4 hours. Build quality is solid, thick polycarbonate housing, sturdy latches, and a smooth-rolling spool holder.

2. SUNLU FilaDryer S2, Best Value ($50)

The SUNLU S2 is the best-selling filament dryer for a reason: it works well enough at a price that makes it an impulse buy. It dried 3.2g of moisture from our test spool, 16% less than the EIBOS, but still enough to eliminate all popping and significantly reduce stringing in the print test.

Temperature accuracy is the weak point: I measured 5-8°C variation from the set point depending on where in the chamber you probe. The bottom near the heater runs hot, the top runs cool. For PLA and PETG this doesn't matter much. For Nylon (which needs precise 70°C sustained heating), the EIBOS is the better choice.

If you're on a budget and mainly print PLA or PETG, the S2 is the smart buy. Spend the $20 savings on a good spool of filament.

3. SUNLU FilaDryer S4, Best Multi-Spool ($120)

If you run multiple printers or cycle through several materials regularly, the S4 holds four spools simultaneously. Each spool sits in its own heated compartment with individual PTFE feed ports. Drying performance per spool matches the S2, not quite EIBOS territory, but effective for most filaments.

At $120, you're paying $30 per spool slot, which is cheaper than buying four individual dryers. The footprint is large (roughly 400 x 400 x 200 mm), so make sure you have the shelf space.

4. Creality Space Pi Plus, Decent but Underwhelming ($60)

The Creality unit looks great, the cylindrical design is distinctive and the touchscreen interface is polished. But drying performance lagged behind both SUNLU and EIBOS units. The lower max temperature (65°C vs 70°C) is a disadvantage for hygroscopic materials like Nylon and ASA, and the weight-loss numbers show it.

5. PolyMaker PolyBox II, Not a Dryer ($55)

Do You Actually Need a Filament Dryer?

If you print exclusively with PLA in a low-humidity environment (below 40% RH) and use spools within a week of opening, probably not. Throw some silica gel packets in a sealed container and you're fine.

But if any of these apply to you, a dryer is one of the best accessories you can buy:

• You print PETG, Nylon, TPU, or ASA, all highly hygroscopic materials
• You live in a humid climate (above 50% RH year-round)
• Your filament sits open for weeks between uses
• You hear popping or crackling from the nozzle during prints
• You see unexpected stringing that retraction tuning can't fix

Proper filament storage prevents moisture absorption in the first place. A dryer rescues filament that's already wet. Ideally, you use both.

The Verdict

Buy the EIBOS Cyclopes if you want the best drying performance and print with multiple material types. Buy the SUNLU S2 if you mostly print PLA/PETG and want the best value. And whatever you do, don't confuse a dry box with a dryer, they solve different problems.