PETG and ASA are both tough, but they belong in different places. PETG is the easy tough filament for indoors. ASA is the outdoor specialist that resists UV damage.

How they compare

The table splits them on the axes that matter. PETG leads ease. ASA leads UV and heat.

PETG versus ASA
PropertyPETGASA
Ease of printMediumHard
UV resistanceLowHigh
Heat resistanceMediumHigh
Outdoor weatheringFairGood
FumesLowStrong
Needs enclosureNoYes
Best forIndoor tough partsOutdoor parts
Green marks the category leader. PETG wins on ease and fumes. ASA wins on UV and heat.

When to pick PETG

Pick PETG for tough parts that stay indoors or in shade. It prints at 240 to 260 °C with no enclosure, per the Prusament PETG datasheet. It is the easier path to a durable part.

When to pick ASA

Pick ASA for parts that see sun or weather. The Prusament ASA datasheet lists a nozzle of 260 °C with a 10 °C margin and a heat deflection of 93 °C. ASA holds color and strength outdoors where PETG yellows and weakens.

Frequently asked

Is PETG or ASA better for outdoor use?
ASA. It resists UV and weather. PETG works for sheltered outdoor use but yellows and weakens in direct sun.
Is ASA harder to print than PETG?
Yes. ASA needs an enclosure and ventilation, and it warps more. PETG prints in open air.
Which is stronger, PETG or ASA?
They are close in toughness. ASA handles more heat and sun. PETG is less brittle and easier to print.
Can I use PETG outside?
For short-term or sheltered use, yes. For lasting sun exposure, switch to ASA.

To go deeper, read the PETG guide or the ASA guide. For related picks, see PETG versus ABS or ABS versus ASA.

Related guides

Sources & methodology

4 citations · reviewed 2026-07-09
  1. 01Prusament PETG Technical Datasheetaccessed 2026-07-06Tier 1
  2. 02Prusament ASA Technical Datasheetaccessed 2026-07-09Tier 1
  3. 03All3DP All 3D Printing Filament Types Explainedaccessed 2026-06-29Tier 2
  4. 043DSourced Complete 3D Printer Filament Guideaccessed 2026-06-29Tier 2
How we vetted this: every claim traces to a tiered source, Tier 1 (manufacturer, slicer, standards) first. Read the full sourcing and conflict-of-interest policy.