A 3D printer is only as good as the filament going into it, and the single biggest variable nobody controls is moisture. PLA from a freshly opened spool prints clean. The same spool three weeks later in a humid garage prints with strings, bubbles, and rough surfaces. The fix is a dedicated filament dryer, and the market has finally moved past the early “small box with a heater” units to dryers that handle dual spools, active drying during printing, and the high temperatures nylon needs. After looking at 14 current dryers across the budget, mid, and enthusiast tiers, these five stood out for temperature accuracy, drying capacity, and build quality.
Quick comparison
| Dryer | Spools | Max temp | Active print | Notes |
|---|---|---|---|---|
| Sunlu S4 | 4 | 70C | Yes | Best capacity |
| Polymaker Polydryer | 1 | 65C | Yes | Compact, premium build |
| Creality Space Pi Plus | 2 | 70C | Yes | Best value dual |
| Eibos Easdry | 2 | 70C | Yes | Best for nylon |
| Sovol SH01 | 1 | 55C | Yes | Best budget |
Sunlu S4, Best Overall
The S4 is the largest dryer on the consumer market and holds four standard 1 kg spools simultaneously. Max temperature is 70C (high enough for nylon and PETG), the heating element is bottom-mounted with a fan that circulates air through the chamber, and a built-in humidity sensor displays current chamber RH on the front panel.
For a print farm or a hobbyist running multiple materials, the S4 is the deck. Drying four spools at once means a Friday-evening drying cycle leaves the weekend free for printing. The exit ports on the side allow active drying during the print, which is the key feature for nylon and TPU.
Trade-off: the unit is large (about 16 by 16 inches of footprint) and the build is plastic. The heating is slightly uneven between the top and bottom shelves, so rotating spools halfway through a long dry helps consistency.
Polymaker Polydryer, Best Premium
The Polydryer is the most expensive single-spool dryer on the market and the build justifies the price. Metal chamber, glass viewing window, accurate temperature control within 1C, and a humidity readout that actually responds to chamber RH rather than just displaying an arbitrary number.
For users running expensive engineering filaments (PA-CF, PPS, PEEK at lower temps), the Polydryer’s accuracy is the reason to pay the premium. The chamber is sealed well enough that a freshly dried spool holds RH below 15 percent for several hours after the dryer is turned off, which matters for transferring to a dry box without reabsorption.
Trade-off: single spool only and the price is roughly four times a budget dryer. For a casual printer, this is overkill. For someone running nylon on a regular basis, it pays back in print success rate.
Creality Space Pi Plus, Best Value Dual
The Space Pi Plus holds two 1 kg spools, hits 70C, and runs about half the price of premium dual-spool dryers. The chamber has top-mounted heating and bottom-mounted humidity sensing, which means the displayed humidity is the relevant number (chamber air at the spool level, not heater air).
For a printer running two-material setups (PLA plus PETG, or PETG plus TPU), the Space Pi Plus is the practical pick. The active print feature works through side exit ports and the unit can run continuously for the entire print without thermal issues.
Trade-off: the door seal is the weak point and ages faster than the rest of the unit. Expect to replace the foam strip after a year of heavy use. Replacement strips are available cheaply.
Eibos Easdry, Best for Nylon and Engineering Filaments
The Easdry is built around a hotter temperature range and a tighter chamber seal than most consumer dryers. Max temperature is 70C in the standard mode and the unit holds the setpoint within 2C across the entire chamber. For nylon specifically (which needs 70C for 12 hours minimum), this consistency matters more than peak temperature.
Two-spool capacity, active print drying, and a chamber that recovers temperature quickly when the door is opened to swap filament. The build is metal-clad with a heavier door than other consumer dryers, which keeps heat in the chamber.
Trade-off: the user interface is dated and the display is small. The unit does what it should but the experience is utilitarian.
Sovol SH01, Best Budget
The SH01 is a single-spool dryer at the bottom of the price range. Max temperature is 55C, which is enough for PLA and TPU but not for nylon or fully drying PETG. The heater is bottom-mounted, the chamber holds a standard 1 kg spool with room for the filament guide, and the unit runs quietly enough to sit next to a printer.
For a beginner printing PLA only, the SH01 is the right entry. The price is roughly one-third the cost of premium units and the function (heat and circulate air around a single spool) is identical to dryers that cost three times more, just at a lower temperature ceiling.
Trade-off: 55C is not enough for nylon and barely enough for PETG. If you plan to print PETG regularly, skip the SH01 and go up to a 70C-capable unit.
How to choose
Match the temperature ceiling to your material
PLA is fine at 50C. PETG wants 65C. Nylon needs 70C minimum. If you only print PLA, a budget 55C dryer covers the case. If you ever print nylon, do not buy a dryer that tops out below 70C. The savings on the cheaper unit get erased by failed nylon prints in the first month.
Capacity matters less than runtime
A four-spool dryer sounds like more capacity, but a one-spool dryer that you run overnight five nights a week dries the same total filament. Buy capacity if you need to dry multiple materials simultaneously. Otherwise the single-spool premium options are usually a better build.
Active print drying for hygroscopic materials
Nylon and TPU reabsorb moisture during a long print. If you regularly run prints over 8 hours, a dryer that supports active drying through a side exit port is the right call. PLA prints are forgiving enough that you can dry, transfer, and print without active drying.
Humidity readout is the diagnostic
The temperature is what does the work, but the humidity readout tells you when the spool is actually dry. A chamber that drops to below 15 percent RH and holds there for a full hour is dry. A chamber that drops to 20 percent and bounces back up is still pulling moisture out of the spool. Cheap dryers with no humidity display work, but you cannot tell when to stop.
For related printing coverage, see our 3D printer FDM vs resin guide for beginners and our breakdown of best 3D filament for heat resistance. For details on how we evaluate printing equipment, see our methodology.
A filament dryer is the cheapest reliability upgrade in a 3D printing setup. The Sunlu S4 covers capacity, the Polymaker Polydryer covers accuracy, and the Sovol SH01 covers budget. Buy the one that matches your material mix and the stringing, bubbling, and clogging problems mostly go away.
Frequently asked questions
How do I know my filament is wet?+
Wet filament makes a cracking or popping sound as it leaves the nozzle, prints with visible strings between travel moves, and shows surface bubbles or rough texture on what should be smooth walls. Nylon and TPU absorb moisture in hours, PETG in days, and PLA in weeks. If a spool has been sitting in a humid room or has been open for more than a few weeks, dry it before the next print and the symptoms usually disappear.
Can I dry filament in a kitchen oven?+
Technically yes, practically no. Most home ovens cannot hold a stable temperature below 100C, and the lowest setting (typically 170F or 75C) will deform PLA spools and warp the wound material. A dedicated filament dryer holds 40C to 70C accurately, which is the range that pulls moisture without softening the plastic. For occasional emergency drying of nylon or PETG only, a convection oven at 60C with a calibrated thermometer works. For anything else, use a real dryer.
Should I print directly from the dryer?+
Yes, especially for nylon, TPU, and PETG. These materials reabsorb moisture from the room air during a long print, and a print that takes 18 hours can finish wetter than it started even if the spool was dry at the start. Active drying during printing keeps the spool at low humidity for the entire job. PLA is forgiving enough that printing from a sealed dry box without active heat is usually fine.
What temperature should I dry each material at?+
PLA dries at 40 to 50C for 4 to 6 hours. PETG at 65C for 6 to 8 hours. ABS and ASA at 65 to 70C for 4 hours. Nylon at 70 to 80C for 12 hours minimum. TPU at 50C for 8 hours (low temp matters; TPU softens faster than other materials). PVA and water-soluble supports need 45C for 8 hours and should always be stored in a sealed dry box because they pull moisture out of the air in minutes.
Do I need a dryer if I store filament in a dry box?+
A dry box with desiccant prevents moisture absorption but does not remove moisture that is already in the spool. If you buy a spool that arrived wet from a humid warehouse, no amount of dry-box storage will fix it. Use a dryer to bring the spool to dry, then move it to a dry box for storage. Once a spool is properly dried, a sealed dry box with fresh desiccant holds it dry indefinitely.
