The best filament dryer for PETG and TPU depends on how many spools you actually keep active. Choose the Creality Space Pi X4 for a four-spool rotation, the Creality Space Pi Filament Dryer Plus for two everyday spools, or the EIBOS Polyphemus when stronger recovery, auto-rotation, or a larger spool matters more than compact size.
Disclosure: GoodPrints may earn a commission from qualifying Amazon purchases made through links on this page, at no added cost to you. This is a specifications-and-buyer-fit guide, not a hands-on test.
Quick verdict: which dryer fits your bench?
| Pick | Best for | Key boundary |
|---|---|---|
| Creality Space Pi X4 | Four open PETG, TPU, support, or color spools | Largest footprint; capacity is wasted if you normally use one or two spools |
| Creality Space Pi Plus | Two-spool everyday drying and print-while-drying use | Less room than a four-spool station and less recovery headroom than the Polyphemus |
| EIBOS Polyphemus | Wetter spools, nylon-adjacent growth, or one large roll | Bigger and more specialized than most casual PETG or TPU users need |
Do not buy on temperature alone. Capacity, air movement, spool fit, feed-port friction, and what happens after drying often matter more than the highest number on the screen.
Best overall for a four-spool PETG and TPU rotation: Creality Space Pi X4
The Space Pi X4 is the strongest fit when moisture control has become a throughput problem. Its current listing describes four-spool capacity, dual independently controlled chambers, up to 85°C, dual 200 W PTC heating, active dehumidification, and desiccant regeneration. The useful part is not simply “more heat.” It is the ability to stage several active spools without repeatedly emptying a smaller box.
That makes sense for a bench running multiple PETG colors, PETG plus support material, or TPU alongside ordinary rigid filament. The two chamber controls can also help when the spool set does not belong in one identical drying cycle. Treat the listing temperature as the machine ceiling, not permission to expose every spool or reel to that temperature. Follow the filament maker's instructions and respect reel heat limits.
Buy it if: three or four open spools are normal, spool swapping is wasting time, and you have the bench space. Skip it if: your real workflow is one PETG spool plus an occasional TPU roll.
Check the current Creality Space Pi X4 listing on Amazon.
For the exact machine decision, read the Creality Space Pi X4 review.
Best compact two-spool pick: Creality Space Pi Filament Dryer Plus
The Space Pi Plus is the cleaner default for many home shops. The maintained current listing is a two-spool dryer with dual 360-degree heating and fans, a touch screen, and support for common 1.75, 2.85, and 3 mm filament formats. Two-spool capacity is enough for paired materials, two colors, or keeping PETG and TPU available without buying a four-spool appliance.
This is the best balance when you want to print from the dryer but do not manage a broad spool backlog. Before buying, check where both filament outlets sit relative to the printer, whether the PTFE path will bend sharply, and whether your preferred spools rotate freely. A dryer can improve filament condition while a poor feed path creates a different problem.
Buy it if: two active spools describe most of your week and footprint matters. Skip it if: you regularly need four spools staged or want the Polyphemus's larger-spool and recovery-first lane.
Check the current Creality Space Pi Filament Dryer Plus listing on Amazon.
See the dedicated Space Pi Plus review for a narrower two-spool decision.
Best for wetter or larger spools: EIBOS Polyphemus
The EIBOS Polyphemus makes more sense when recovery strength is the real purchase driver. Its current listing describes up to 80°C, auto-rotation, auto-humidity hold, 360-degree heating, and room for a 3 kg spool. It can also accommodate two ordinary spools, but its value proposition is different from simply maximizing spool count.
Auto-rotation aims to expose the spool more evenly during a longer cycle, while auto-humidity hold supports a ready-to-print station after the active recovery phase. That is useful for a stubborn PETG roll, TPU that has been left exposed, or a workshop moving toward more moisture-sensitive materials. It is not a magic fix for burned filament, a partial clog, excessive nozzle temperature, or a poor retraction profile.
Buy it if: you need serious recovery, use larger rolls, or keep losing time to moisture-sensitive materials. Skip it if: your spools are normally fresh and sealed or a smaller two-spool dryer already covers the workload.
Check the current EIBOS Polyphemus listing on Amazon.
The EIBOS Polyphemus review covers the larger-spool and hotter-material lane in more detail.
PETG versus TPU: the dryer job is not identical
PETG usually rewards a simple dry-and-retest workflow
Wet PETG can show extra stringing, popping, rough surfaces, inconsistent extrusion, or a hazier finish. Those symptoms are not exclusive to moisture, so use a controlled test: dry one known spool according to its maker's guidance, keep the printer profile unchanged, and reprint the same small part. If the symptoms improve, moisture was part of the problem. If nothing changes, inspect temperature, nozzle condition, flow, and travel behavior before buying more storage gear.
TPU adds feed-path sensitivity
TPU can benefit from drying, but flexible filament also exposes resistance in the path from dryer to extruder. Long tubes, tight bends, rough outlet edges, or a spool that does not turn freely may cause under-extrusion even when the material is dry. Put the dryer where the path stays short and gentle, then test a steady extrusion pattern before committing a long flexible job.
How to choose without overbuying
- Count active spools, not owned spools. A shelf of sealed filament does not automatically justify a four-spool dryer.
- Separate recovery from maintenance. Recovering a neglected roll asks more of a dryer than keeping a recently opened PETG spool ready.
- Measure the bench. Include lid clearance, rear ports, PTFE bends, power-cord space, and access to the controls.
- Check reel tolerance. The dryer may reach a high air setpoint while a cardboard or low-temperature reel remains the limiting part.
- Plan post-dry storage. A warm spool can absorb moisture again. Use sealed storage with maintained desiccant when the spool leaves the dryer.
Dryer, dry box, or sealed storage?
An active dryer removes moisture. A dry box or sealed container mainly slows moisture from returning. If the spool already prints badly, passive storage is not a substitute for a proper drying cycle. If the spool prints well and simply needs protection between jobs, heating it repeatedly may be unnecessary. The broader dryer-versus-dry-box-versus-storage guide separates those jobs.
For material-specific boundaries, use the dedicated PETG dryer guide or TPU dryer guide.
A practical acceptance test after purchase
- Choose one spool with repeatable moisture symptoms and photograph or save the failed test part.
- Record the filament brand, material, reel type, maker-recommended drying guidance, dryer setting, and cycle length.
- Confirm the spool rotates without scraping and the outlet path does not tug on the extruder.
- Print the same file with the same profile immediately after the cycle.
- Compare stringing, surface texture, popping, extrusion consistency, and part mass if you track it.
This proves whether the dryer helped your actual material. It is more useful than assuming a higher displayed temperature or a larger box must produce a better print.
Frequently asked questions
What is the best filament dryer for PETG?
For a four-spool rotation, the Space Pi X4 is the strongest current fit here. For one or two normal spools, the Space Pi Plus avoids unnecessary footprint. Choose based on active capacity, not the number of rolls you own.
What is the best filament dryer for TPU?
The same capacity split applies, but TPU makes outlet position and feed resistance especially important. The best dryer is the one that can condition the spool without forcing the flexible filament through a long, high-friction route.
Does a dryer stop PETG or TPU stringing?
Only when moisture is a meaningful cause. Temperature, travel, retraction, nozzle buildup, and feed resistance can create similar symptoms. Dry one spool and repeat one controlled print before changing multiple settings.
Should filament stay in the dryer while printing?
It can be useful for long jobs and moisture-sensitive materials, provided the spool moves freely and the feed path is clean. For short jobs with properly conditioned PETG, sealed storage between prints may matter more than continuous heat.
Bottom line
Choose the Creality Space Pi X4 when four active spools justify the room. Choose the Space Pi Plus when two-spool convenience matches a normal home-shop workload. Choose the EIBOS Polyphemus when recovery strength, auto-rotation, or a larger roll is the problem you are actually paying to solve. If you cannot name which of those three jobs belongs to your bench, start with a controlled dry-and-retest cycle and avoid buying capacity you will not use.