The best filament dryer for PETG and TPU depends on chamber layout and the exact spools you plan to pair, not just capacity. Choose the Creality Space Pi X4 for a four-spool rotation that benefits from two independently heated chambers, the Creality Space Pi Filament Dryer V2 Plus for two everyday spools that can safely share one condition, or the EIBOS Polyphemus when rotation, a wider single-spool path, or recovery-first control matters more than separate zones. If PETG and TPU do not share a manufacturer-supported drying range and reel limit, dry them separately.
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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 V2 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.
Official facts checked September 18, 2026: Creality's current pages describe the SpacePi X4 as a four-spool, dual-independent-chamber dryer with a machine ceiling of 85°C and the two-roll model as the Space Pi Filament Dryer V2 Plus with a 45-70°C range. EIBOS lists the Polyphemus at 30-80°C with exact standard and expansion-part spool envelopes. These are machine specifications, not universal filament prescriptions.
Can PETG and TPU share one dryer cycle?
Sometimes, but only when the exact PETG, TPU, and both reels support the same temperature and time. A two-spool box does not create two temperature zones. Use the lowest common manufacturer-supported cycle or separate the spools; do not average two incompatible recommendations.
| Dryer layout | What it lets you do | Stop condition |
|---|---|---|
| Space Pi V2 Plus: one shared 45-70°C chamber | Condition two rolls together only when their exact material and reel limits overlap | Separate cycles if either maker specifies a different range or the reel rating is unknown |
| Space Pi X4: two independently heated chambers, up to 85°C | Run different supported conditions in the two chambers; spools inside one chamber still share its environment | Do not treat 85°C as a PETG, TPU, cardboard-reel, or plastic-reel instruction |
| Polyphemus: one 30-80°C rotating chamber | Use two spools up to 210 x 80 mm each or one up to 210 x 170 mm in the standard envelope | A spool up to 250 x 170 mm needs the listed expansion parts; verify that the exact offer includes or supports them |
Bambu's current drying-function warning is a useful cross-check: high-temperature ABS or PETG drying can exceed the softening temperature of PLA and TPU. That does not set the right cycle for every brand, but it is a clear reason not to place an unknown TPU reel beside PETG at a hotter PETG setting.
Use limit: a chamber setpoint or humidity display does not prove filament-core temperature, residual moisture, reel safety, or production readiness. EIBOS explicitly says its humidity value shows changes in the chamber environment rather than filament moisture content. Qualify the exact spool with a repeatable print, then keep heat-, load-, sealing-, chemical-, fatigue-, or dimension-critical parts on their own complete-part release plan.
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 V2 Plus
The Space Pi V2 Plus is the cleaner default for many home shops. Creality's current product page uses the V2 Plus name and specifies two-roll capacity, one 45-70°C chamber, real-time temperature and humidity monitoring, and a 0-48 hour timer. The exact Amazon offer retained here still titles the product Space Pi Plus, so match the housing, controls, electrical region, and seller record instead of assuming every similarly named used or marketplace unit is the same revision.
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 V2 Plus listing on Amazon.
See the dedicated Space Pi V2 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. EIBOS currently specifies 30-80°C, automatic rotation, humidity-control mode, two standard spools up to 210 x 80 mm each, or one standard-envelope spool up to 210 x 170 mm. The larger 250 x 170 mm path depends on expansion parts, so a marketplace phrase such as "3 kg spool" is not proof that the exact offer includes the required extension.
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, follow the ordered PETG stringing diagnosis before buying more storage gear or changing several settings at once.
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 post-purchase acceptance test
- 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 V2 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 V2 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.