SpoolIndex

The Filament Price Index

ABS vs ASA Filament: Cost, UV Resistance, and When Each One Wins (2026)

ASA typically costs 30 to 50 percent more per kg than ABS, but it is the right call for anything that lives outside or in direct sun. For enclosed indoor parts, ABS is still the better value.

ABS and ASA are close cousins. ASA was developed specifically to keep almost everything people liked about ABS, while fixing the one thing ABS does badly: surviving sunlight. They share a print profile, they share a use-case category (tough, heat-resistant functional parts), and on most mechanical specs they are within a few percent of each other. The interesting differences are price and UV behavior. On the retailers SpoolIndex tracks, mainstream ABS lands in the $16 to $25 per kg range for budget and mid-tier spools, and $20 to $30 per kg for engineering-grade brands. ASA runs roughly $25 to $40 per kg for mainstream spools, and $30 to $45 per kg for engineering grade. Expect ASA to cost 30 to 50 percent more than the equivalent ABS from the same brand. The premium is not arbitrary. ASA replaces ABS's polybutadiene rubber phase with an acrylate, which is more expensive raw material. ASA also sells in lower volume than ABS, and a larger share of the ASA market is sourced from name-brand resin producers like LG Chem and Ineos, so there are fewer house-brand budget options to drag the floor down. On mechanical numbers ABS and ASA are close enough that strength alone almost never decides the purchase. Tensile strength, stiffness, and heat deflection are all in the same neighborhood. ABS has marginally higher impact resistance in some tests; ASA holds up slightly better at sustained temperature. For 95 percent of parts, treat them as mechanically equivalent and pick on environment. The UV gap is the real story. ABS yellows visibly within weeks of direct outdoor sun and gets brittle within a year. Cracks, fading, and chalky surfaces follow. ASA keeps its color and toughness for years in the same conditions. If a part is going to live on a deck, a roof, a dashboard, a garden, or anywhere it sees real sunlight, that single fact decides the material. Printability is the small print that matters. Both want a heated bed (90 to 110 C) and an enclosure. Both produce styrene fumes you do not want to breathe for hours, so ventilation matters. ASA warps slightly less than ABS and lays down marginally cleaner layers in practice, which means fewer failed prints once you have your profile dialed in. Neither material is a good fit for an open-frame printer in a cold garage.

FAQ

How much more does ASA cost than ABS?
Typically 30 to 50 percent more per kg from the same brand. In 2026, mainstream ABS sits around $16 to $25 per kg and ASA around $25 to $40 per kg. Engineering-grade ASA runs higher, $30 to $45 per kg, where engineering ABS tops out closer to $30. The exact premium depends on brand and pack size.
Is ASA worth the extra money over ABS?
Yes, if the part will see sunlight. ABS yellows in weeks of outdoor exposure and turns brittle within a year. ASA holds up for years in the same conditions. For indoor or enclosed parts, the ASA premium buys you nothing meaningful and ABS is the better value.
Will ABS work outdoors if I paint or coat it?
A UV-resistant paint or clear coat can extend ABS's outdoor life significantly, but coatings chip, miss seams, and add labor. If the part is small and easy to recoat, painted ABS is a fine workaround. For anything you do not want to maintain, ASA is the simpler answer.
Does ASA need an enclosure?
Effectively yes. ASA warps less than ABS but it still cracks and delaminates without a stable warm chamber on anything but small parts. Skip the enclosure and you will fight the same problems people fight with ABS, just with more expensive filament.
Is ASA harder to print than ABS?
Slightly easier in practice. ASA warps a little less and tends to bond layers more reliably, so once your profile is dialed in failure rates drop. The settings are nearly identical to ABS though, so anyone already printing ABS can move to ASA without relearning.
Which is stronger, ABS or ASA?
They are close enough that for most parts it does not matter. ABS edges ASA on impact resistance in some tests. ASA holds up better under sustained heat and any UV exposure at all. If maximum impact strength is the spec, ABS wins narrowly. For everything else, treat them as equivalent.
Can I print ASA on a Bambu, Prusa, or Creality printer?
Yes on all three, with the right setup. You need a hotend that hits 235 to 260 C, a heated bed that hits 90 to 110 C, and an enclosed build chamber. Bambu X1 and P1 series with the enclosure handle ASA out of the box. Open-frame Prusa MK4 and Creality machines need an aftermarket enclosure to print ASA reliably.
Is ASA safer than ABS to print indoors?
Not meaningfully. Both release styrene and other VOCs while printing. Both want an enclosure with filtered exhaust or a printer in a ventilated room. Treat them the same way: do not run either one for hours in a closed living space.
When does it make sense to buy ABS over ASA?
Whenever the part stays indoors or out of direct sunlight. Tool holders, machine brackets, enclosure parts, fixtures, and anything inside a cabinet are all fine in ABS. You save 30 to 50 percent per kg and get effectively the same mechanical performance for that use case.
Is cheap ASA worth it, or should I stick to known brands?
Cheap ASA is rarer than cheap PLA or ABS because the market is smaller and most spools come from engineering-grade brands. When budget ASA does show up, check the seller's history and reviews carefully. A failed outdoor part you have to reprint a year later costs more than the $5 per kg you saved at checkout.
The short version: if the part lives in sunlight, buy ASA. If it lives indoors or inside an enclosure, buy ABS and pocket the difference. Either way, plan for a heated bed, an enclosure, and ventilation; both materials are unforgiving without those. SpoolIndex tracks live price per kg for both materials. The ABS index at /material/abs and the ASA index at /material/asa make the premium visible at a glance on any given week, so you can see whether ASA is running its normal 30 to 50 percent gap or whether a sale has temporarily closed it. Pack-view shows multipack price per kg, which is often where ABS in particular gets cheap. A note on incentives: SpoolIndex earns affiliate commissions on some outbound clicks, but rankings are based on observed price and value, not on which retailer pays the most. The cheapest credible spool wins the top of the list regardless of who is paying us.

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