Neither acrylic nor polyester is universally better. Each outperforms the other in specific areas, so the right choice depends on what you’re using the fabric for. Acrylic wins on warmth, UV resistance, and color retention. Polyester wins on durability, moisture management, and environmental impact. Here’s how they compare across the categories that matter most.
Warmth and Insulation
Acrylic is the warmer fiber. It’s often called “artificial wool” because it mimics wool’s soft, insulating feel. Research from Oregon State University found that thermal insulation in fabrics depends primarily on thickness and air-trapping ability rather than fiber content alone. When blankets of equal thickness were compared, acrylic, wool, and blended fabrics transmitted similar amounts of heat. But acrylic fabrics tend to be loftier, meaning they trap more still air and insulate better in practice.
Polyester can be engineered for warmth (think fleece jackets), but standard polyester fabrics are thinner and less naturally insulating than acrylic knits. If you’re shopping for a warm sweater, scarf, or blanket and wool is out of your budget, acrylic is the closer substitute.
Durability and Pilling
Polyester is the stronger, more durable fiber overall. It resists stretching, shrinking, and wrinkling better than acrylic. Polyester garments hold their shape through hundreds of wash cycles, which is why it dominates activewear and everyday basics.
Pilling is where things get interesting. In Martindale abrasion testing, which rubs fabric against a surface thousands of times to simulate wear, polyester actually pills more readily than acrylic. Polyester fabric reached the worst pilling grade (1.0) after just 2,000 rubs against wool abradant, while higher-modulus acrylic fibers showed less tendency to pill. That said, polyester pills tend to break off over time because the fiber is strong enough to hold them temporarily but not indefinitely. Acrylic pills can cling stubbornly. In real life, both fabrics pill, but polyester garments generally look better longer because of their superior overall abrasion resistance.
UV Resistance and Color Retention
Acrylic is significantly better in sunlight. It’s the go-to fabric for outdoor cushions, awnings, boat covers, and patio umbrellas because it resists UV degradation far better than polyester. In marine fabric ratings, acrylic earns a 5 out of 5 for both UV resistance and colorfastness, while polyester scores a 4 out of 5 in each category.
The practical difference is substantial over time. Polyester starts losing strength within the first five years of constant sun exposure and fades noticeably in high-sun environments. Acrylic holds its color and structural integrity for years even in tropical and coastal conditions. If you’re choosing fabric for anything that lives outdoors permanently, acrylic is the clear winner. For seasonal or shaded use, polyester performs fine and costs less.
Moisture and Quick Drying
Both fibers are hydrophobic, meaning they repel water rather than absorbing it. Polyester and acrylic each adsorb no more than about 2% water by mass even in high-humidity conditions. But polyester has a slight edge: it picks up the least moisture of any common fabric fiber, sitting below acrylic (which in turn sits below nylon and cotton).
This matters for activewear. Polyester wicks sweat away from your skin and dries quickly, which is why nearly all performance athletic clothing uses polyester or polyester blends. Acrylic doesn’t wick as efficiently and tends to feel clammy during intense exercise. For workout gear, base layers, or anything where sweat management matters, polyester is the better choice.
Comfort and Skin Sensitivity
Acrylic is softer to the touch and closer to wool’s feel, which makes it popular for sweaters, hats, and blankets. Polyester can feel slick or plasticky in cheaper garments, though high-quality polyester microfibers have largely closed that gap.
For skin sensitivity, neither fiber is a common allergen in its finished fabric form. The concern with acrylates (the chemical family behind acrylic) comes mainly from occupational exposure to uncured monomers during manufacturing, not from wearing finished garments. Published cases of acrylate contact dermatitis involve industrial workers, dental professionals, and people exposed to liquid or partially cured acrylate products. Once acrylic fiber is fully polymerized into fabric, residual monomer levels are extremely low. If you have sensitive skin, the bigger factor is usually the dyes and finishing chemicals applied to either fabric, not the fiber itself.
Environmental Impact
Polyester is the more environmentally responsible option of the two, though neither is great. Both are petroleum-based plastics that don’t biodegrade, but acrylic sheds dramatically more microplastic pollution.
In laboratory washing and drying tests published in the journal Polymers, acrylic fabric released roughly 1,428 parts per million of microplastics per cycle, compared to 592 ppm for polyester and 199 ppm for nylon. That means acrylic sheds nearly 2.5 times more microplastic than polyester with every wash. Acrylic was also unusual in that it released 50% more microfibers during machine drying than during washing, while polyester shed more during the wash cycle itself.
Polyester also has a recycling advantage. Recycled polyester (made from plastic bottles or reclaimed fabric) is widely available and increasingly common in clothing. Recycled acrylic is rare because the fiber’s chemical structure makes it harder to break down and reform. If reducing your environmental footprint matters to you, polyester is the better pick.
Cost and Common Uses
Polyester is generally cheaper and more widely available. It’s the world’s most-produced fiber, used in everything from t-shirts to bedsheets to industrial materials. That scale keeps prices low.
Acrylic costs slightly more and occupies a narrower niche. You’ll find it in knitwear (sweaters, scarves, beanies), blankets, upholstery, and outdoor fabrics. It’s rarely used for woven garments like dress shirts or pants because it doesn’t drape or breathe as well as polyester in those applications.
Which to Choose by Use
- Winter sweaters and blankets: Acrylic. Softer, warmer, closer to wool’s feel.
- Workout and activewear: Polyester. Better moisture wicking and durability.
- Outdoor furniture and awnings: Acrylic. Superior UV and fade resistance.
- Everyday clothing: Polyester. Holds shape, resists wrinkles, washes easily.
- Eco-conscious shopping: Polyester, especially recycled. Far less microplastic shedding.
- Craft yarn and knitting: Acrylic. Affordable, soft, and available in vibrant colors that last.