Use PLA for anything that lives indoors at room temperature and needs to look good. Use PETG when the part will be knocked, flexed, left outside or kept wet. PETG’s heat advantage is real but small, about 8 to 13 °C on the data sheets, so if heat is the actual problem you probably want ASA or ABS, not PETG.
The numbers, from maker data sheets
These ranges come from the technical data sheets behind our filament temperature table: Bambu Lab, Prusament and Polymaker for PLA, and Bambu Lab, Prusament and eSUN for PETG.
| PLA | PETG | |
|---|---|---|
| Nozzle | 190 to 230 °C | 230 to 260 °C |
| Bed | 25 to 60 °C | 65 to 90 °C |
| Drying | 50 to 55 °C for 6 to 8 h | 60 to 65 °C for 8 h |
| Density | 1.17 to 1.24 g/cm³ | 1.27 to 1.28 g/cm³ |
| Heat deflection (ISO 75) | 54 to 60 °C | 62 to 69 °C |
| Enclosure | not needed | not needed |
Every one of the 25 machines in our printer database reaches PETG temperatures. The lowest nozzle maximum on the list is 260 °C and the lowest bed maximum is 80 °C. So this is a choice about the part, not about the printer.
Heat: compare like with like
Heat deflection temperature (HDT) is the temperature at which a test bar bends a set amount under a set load. The load matters. ISO 75 is usually run at 0.45 MPa or at 1.8 MPa, and the heavier load gives the lower number. Quoting a PLA figure at one load against a PETG figure at the other makes the gap look bigger or smaller than it is.
Same brand, same load:
| Brand | PLA at 0.45 MPa | PETG at 0.45 MPa | Gap |
|---|---|---|---|
| Bambu Lab PLA Basic and Bambu Lab PETG HF | 57 °C | 69 °C | 12 °C |
| Prusament PLA and Prusament PETG | 55 °C | 68 °C | 13 °C |
At 1.8 MPa the Bambu pair reads 54 °C and 62 °C, a gap of 8 °C. Polymaker’s PolyLite PLA data sheet gives 60 °C at 0.45 MPa, which is only 8 or 9 °C short of those PETG figures. eSUN’s PETG page lists 64 °C without stating the load, so it cannot be placed in the table.
Here is what that means in practice. If a PLA part sagged somewhere warm, PETG buys you roughly ten degrees of margin. That may be enough, and it may not. ASA data sheets in our database, Bambu Lab’s ASA data sheet among them, run 92 to 100 °C on the same test, which is a different league. We have not tested any of these parts ourselves. This is what the makers publish.
Toughness and surface
Prusa’s material pages are blunt about both. PLA, per Prusa’s PLA guide: easy to print, good detail, low warping, but “brittle and inflexible” with low UV and temperature resistance, and not suitable for technical or outdoor use. PETG, per Prusa’s PETG guide: tough and durable, good layer adhesion, low warping, water and humidity resistant, suited to mechanical parts indoors and out. Prusa prints parts of its own printers in PETG.
PETG’s listed drawbacks are the ones you see on the bed: possible stringing, poor bridging and overhangs, “not great for printing detailed parts”, and supports that are hard to remove. It also bonds very strongly to the print surface. Prusa warns that printing PETG on a smooth PEI sheet might damage the sheet and recommends a textured or satin sheet instead. Check what your own printer’s maker says about your plate before the first PETG print.
So for a figurine, a lithophane or anything with small text, PLA is the better material and it is not close. PETG does not make a model “stronger” in any way you would notice on a shelf, and it will look worse.
Speed and drying
PETG is slower at the limit. Prusa’s guidance on maximum volumetric speed gives typical ranges of 12 to 20 mm³/s for PLA and 8 to 15 mm³/s for PETG, because PETG is more viscous. On a fast printer where the hotend is the bottleneck, that is a real difference in print time. You can see what it does to your speeds in the volumetric flow calculator.
PETG also wants more care with moisture: a hotter and, at the low end, longer drying cycle (60 to 65 °C for 8 hours against 50 to 55 °C for 6 to 8). Prusa’s filament drying guide notes that PLA does not change much as it takes on humidity. Wet PETG strings, and PETG already strings. The drying chart has the per-brand figures.
A worked example: what a kilogram gets you
PETG is denser, so a 1 kg spool holds less length. For 1.75 mm filament, one meter weighs 2.98 g in PLA at 1.24 g/cm³ and 3.05 g in PETG at 1.27 g/cm³. That makes about 335 m per kilogram of PLA and 327 m of PETG.
The same printed part, same volume, therefore weighs 2.4 percent more in PETG (1.27 / 1.24). A 100 g PLA part becomes 102.4 g. At equal spool prices the PETG part costs 2.4 percent more in material. That is small enough to ignore when choosing, but it is why a slicer estimate in grams changes when you switch the filament profile and nothing else. The filament length and weight calculator does this for any density.
What I would buy
If you own one spool, make it PLA. It prints on every machine, with the bed barely warm, and it forgives a damp garage better than PETG does.
Buy PETG for the specific jobs it wins: brackets, clips and mounts that take load or shock, anything outdoors, anything that gets wet. Do not buy it as a heat upgrade for a part that failed in PLA unless you know the part only needs another ten degrees. For that job look at ASA, and check first whether your printer is enclosed.
And ignore the generic ranges above once you have a spool in hand. Bambu’s PETG wants a 65 to 75 °C bed and eSUN’s wants 75 to 90 °C. The label on the spool beats any table, including ours.
