Best Filament Dryer 2026: Compared 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 the market runs from passive dry boxes to four-spool heated cabinets, and the labels on the box rarely make the difference obvious. This is a comparison of five widely sold units on the specifications their makers publish: maximum temperature, how many spools fit, whether there is a heater at all, and whether you can read the humidity inside. It is not a measurement of our own.

How the five compare

Manufacturer specifications as published by Polymaker, SUNLU, EIBOS and Creality and their retailers, checked October 2026. Prices move, so they are not listed here: follow the link for the current one.

1. EIBOS Cyclopes: the one to pick if you print more than PLA

The Cyclopes uses a sealed circular chamber with a heated base plate and active fan circulation, where several competitors heat from the bottom only. It is rated at 100 W and reaches 70 °C, which is the range nylon and PC need. Spool capacity is the most flexible of the group: two 1 kg spools, four 0.5 kg spools, or a single 3 kg spool.

The built-in humidity readout shows the relative humidity inside the chamber, which is the only way to tell that a spool is actually dry rather than merely warm. The housing is thick polycarbonate with sturdy latches and a smooth-rolling spool holder.

2. SUNLU FilaDryer S2: the cheapest way to get an actual heater

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 reaches the same 70 °C as the more expensive units, but from a 48 W element rather than 100 W, and it holds a single spool of at most Ø 210 × 85 mm.

The trade-off is the single small chamber with one fan: heat is less evenly distributed than in a unit built around circulation, and anything larger than a standard 1 kg spool will not fit. For PLA and PETG that is rarely a problem. For nylon, which wants sustained heat near the top of the range, the Cyclopes is the safer choice.

If you mainly print PLA or PETG and want one spool dry at a time, the S2 does that and little else: which is the point.

3. SUNLU FilaDryer S4: four spools at once

If you run several printers or rotate through materials, the S4 takes four 1 kg spools at once, with eight filament outlets and three circulation fans behind a PTC heater that retailers list between 330 and 350 W. It reaches the same 70 °C as the smaller units; what you buy is throughput, not a higher ceiling.

Per spool slot it costs clearly less than four separate dryers. The footprint is the catch: roughly 460 × 220 × 310 mm and about 4 kg, so measure the shelf first.

4. Creality Space Pi Plus: two spools and a timer

The cylindrical design is distinctive and the interface is the most polished here. It holds two rolls, heats them with dual PTC elements over a 45–70 °C range, and lets you set a drying time of up to 48 hours: useful for nylon, which can want a very long cycle. Retailers disagree on its power rating, quoting anywhere from 110 to 300 W, so treat Creality's own spec sheet as the authority.

5. Polymaker PolyBox II: storage, not drying

What temperature does your filament actually need?

The 70 °C ceiling shared by every heated unit in this list is not an arbitrary number, and it matters more for some materials than others. Published drying guidance from filament and dryer makers clusters like this, though spools differ and the one on your shelf has the final say:

The other rule worth keeping: stay under the material’s softening point. A spool that slumps in the chamber is worse than a damp one, because the winding tangles and the filament snags on its way out. When a spool is badly saturated, add time rather than heat.

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

Take the EIBOS Cyclopes if you print more than PLA and want spool-size flexibility; take the SUNLU S2 if one spool at a time is enough and you want the lowest price that still includes a heater; take the S4 if you need four at once. And whatever you do, don't confuse a dry box with a dryer: they solve different problems, and only one of them removes moisture.