Filament Dryers for PLA

Start from the temperature your PLA needs

PLA makers publish lower drying temperatures than most dryers can reach, so the useful question is not "how hot does it go" but "can it hold a low setting steadily". Here is what four manufacturers list for their PLA:

So a dryer for PLA must be able to sit anywhere from 45 to 55°C and stay there for six hours or more. Look for a dial or menu that sets temperature in small steps, not just a few fixed presets labeled by material, because a preset called "PLA" may not match your brand's figure. Full drying procedures by brand are in our guide on how to dry PLA filament; this page is about choosing the box itself.

Why a higher maximum is not a selling point for PLA

Dryer listings often lead with their top temperature, but that number serves nylon, polycarbonate and other engineering plastics. SUNLU's lineup shows the spread: the FilaDryer S1 Plus has a setting range of 35 to 55°C (opens in a new tab), the S2 runs 35 to 70°C, and the E2 lists a maximum of 110°C with 90°C mentioned for PA and PC. Polymaker says its PolyDryer's highest range is 68 to 73°C (opens in a new tab). Every one of those covers PLA's band.

Extra heat is a risk rather than a benefit if you only print PLA. Prusa warns that exceeding the drying temperature means the filament will soften and stick together (opens in a new tab). The spool can matter too: Prusa says its older black spools are safe only up to 45°C and need a long screw to hold them together above that, while spools made since October 2025 resist up to 90°C. If you print PETG as well, which Prusa dries at 55°C, a 35 to 55°C unit still covers both. Pay for 70°C or more only when a material you actually own calls for it.

Capacity: count spools, not liters

Manufacturers state capacity in spools, and that is the figure to compare. From SUNLU's own pages:

• FilaDryer E2: two 1kg spools or one 2kg spool.
• FilaDryer SP2: two 1kg spools or one spool of 2 to 3kg.
• FilaDryer S4: up to four 1kg spools at once.

Polymaker's PolyDryer box takes spools up to 1kg, and the PolyDryer XL holds 3kg spools. Work out capacity from how you print. If you run one printer from one spool, a single-spool unit is enough. If you feed a multi-color system or keep several colors in rotation, size for the number you would want dry at the same moment. Bulk buyers with large spools should confirm a dryer accepts 2kg or 3kg reels before anything else, since many single-spool boxes are sized for 1kg only.

Spool size fit

"Fits a 1kg spool" is not a measurement, and spool dimensions vary by brand, especially between plastic and cardboard reels. Measure the outer diameter and width of the spools you buy most and compare them with the dryer's stated limits. SUNLU gives a clear example for the SP2: spool diameters up to 250mm and widths up to 153mm (opens in a new tab). Some listings give only the chamber size instead; SUNLU lists the S2's maximum capacity as a space 210mm across and 85mm high, so a spool lying flat in it needs to be under 85mm wide.

Check how the spool sits inside, too. Rollers or bearings let it turn freely for printing, while a fixed hub may not suit spools with an unusual center hole. Cardboard reels are the usual trouble spot: Prusa notes that some third party spools, especially cardboard ones (opens in a new tab), may need adapters in its drybox, and the same caution applies to any roller design.

Feeding while drying

A dryer that doubles as a feed box lets you dry and print in one step, and keeps the active spool warm for long jobs. Prusa notes that with a dedicated dryer you can often keep the spool inside while printing (opens in a new tab). SUNLU lists the S4 as supporting simultaneous feeding to up to four printers, and its AMS Heater as supporting drying while printing.

When a listing claims feeding, check the outlet: where the filament exits relative to your printer's spool holder or feeder, whether a PTFE tube fitting is included, and whether the path bends sharply. A tight or long tube adds drag. Prusa's advice for its drybox applies to any feed box: cut the tube to length and keep it free of slack. If you feed a multi-spool system, also confirm the dryer can sit close enough to it.

Humidity readouts: treat them as claims

Many dryers show a humidity percentage. It is useful as a trend, but read the number with caution. The sensor reports the air in the chamber, not the moisture inside the filament, and small sensors have tolerances. Prusa states its drybox hygrometer is accurate to plus or minus 3% RH (opens in a new tab) and can take up to an hour to settle. Polymaker notes the PolyDryer hygrometer's minimum readout is 10%, so a reading at the bottom of the scale does not tell you how much lower the air actually is.

Automatic humidity control is a related claim. SUNLU says the S4 starts when humidity reaches a set range of 30 to 50% and stops at 25%. Features like this are handy for storage between prints, but judge them by the manufacturer's stated behavior rather than expecting a display to confirm the spool is fully dry. The real check is a print: popping, bubbles and rough walls should disappear after a full drying cycle. Our stringing guide helps separate moisture from settings problems.

A short checklist before you buy

1. Confirm the dryer can be set to your PLA brand's temperature, in steps of 5°C or finer.
2. Match capacity to how many spools you want dry at once.
3. Compare your spools' measured diameter and width with the stated limits.
4. If you want to print from it, check the outlet, tube fitting and rollers.
5. Read the humidity display as a guide, and judge success by print quality.

The grid on this page shows dryers in stock, with each price stamped with the time it was verified against Amazon; prices older than 24 hours show "Check price at Amazon" instead.

Frequently asked questions

What temperature should a filament dryer reach for PLA?

It needs to cover roughly 45 to 55°C, which spans the PLA settings published by Prusa, Anycubic, SUNLU and Polymaker. Use your own brand's figure rather than a generic preset.

Can a filament dryer replace a dry box?

Partly. Many dryers keep spools sealed and some hold humidity automatically between prints, but they take up more space and power than a passive box. Most people with several spools use both; see filament storage.

Is a dual-spool dryer worth it for one printer?

It helps if you swap colors often or want the next spool ready while the current one prints. With a single color in use, a one-spool unit is enough.

Do I need a dryer that reaches 70°C or more?

Only for materials that call for it, such as nylon or polycarbonate. PLA's published drying settings stop at 55°C in the sources above.