Should you wear a fleece or a wool layer when you head out on your next cool-weather adventure? As you’re pondering which sweater or sweatshirt to grab in preparation, you may well wonder whether fleece or wool will work best for your activity. Which will be most comfortable while providing the best protection from the elements? The answer depends on what the weather’s like and what you’re planning on doing. Is it windy and/or likely to rain or snow? What is your anticipated level of exertion? For example, are you going shopping, or taking a long hike with the dog? All these variables will inform your decision: fleece, or wool?
What Is Fleece?
Fleece, also known as polar fleece, is a synthetic fabric made of polyester or a blend, originally invented to imitate wool. During manufacture, the fabric is brushed to give the synthetic fibers more volume, making the material soft and “fuzzy” like sheep’s wool fleece (sometimes mimicking sherpa and shearling wool).
Fleece vs. Wool
Comparing fleece and wool gives rise to some confusing terminology. Sometimes you’ll hear the term “wool fleece,” which is a natural fiber that covers the skin of sheep and similar mammals, functioning like human hair or other animal furs. The fibers are collected via shearing and processed into the fabric we know simply as wool. The term “wool fleece” refers to this unprocessed wool. The final wool textile, which we simply call “wool,” has been used for thousands of years to produce garments that keep us warm, including sweaters.
Synthetic fleece, which is simply called “fleece,” is a material made from polyester (usually) and its name is inspired by the natural textile it mimics. The difference between fleece and wool, generally, is that wool is a natural fabric that comes from animals and fleece is a man-made material. But there are many more characteristics of the two textiles like warmth, water repellency, durability, and antimicrobial properties, which we’ll describe below.
Which Is Warmer—Wool or Fleece?
Since warmth originates with the heat of your body, a better way to compare the two fabrics is to consider which insulates better. Both fleece and wool retain heat effectively in the absence of rain or wind. If you get caught in the rain, wools like merino provide better insulation, at least initially, because they contain lanolin, a natural water repellent. But once it’s soaking wet, wool takes a long time to dry. Fleece, on the other hand, becomes saturated with rainwater more quickly than wool, making it useless as an insulating layer when wet, but it dries out much faster when you find shelter from the rain.
In general, wool provides better insulation from the wind, unless you wear a fleece with integrated wind-resistant insulation. But if you’re engaged in a high-intensity activity like running, hiking or biking, this sort of wind-resistant insulation can become too much of a good thing, causing you to sweat—which is counter-productive in cold weather.
Either way, both fleece and wool are far better than cotton in all aspects except cooling. Fleece and wool are warmer, more water-resistant, warmer when wet, and wick perspiration better than cotton.
Pros and Cons of Wool and Fleece
The comfort and performance of both fleece and wool apparel depend in large part on the quality of the apparel. All things being equal, the following is a summary of the pros and cons of wool and fleece sweaters or sweatshirts:
- Quick drying
- Easy maintenance
- Does not shrink like wool
- Very soft and not itchy like some wools
- Low water resistance
- No insulation value when wet
- Can melt near the fire or in a hot dryer
- Can pill over time
- Somewhat water repellent
- Insulates when wet
- Flame retardant
Naturally antimicrobial (resists stink)
- High maintenance
- Slow drying
- Shrinks if washed and dried incorrectly
The Wicking Properties in Fleece vs. Wool
It’s difficult to compare all fleeces to all wools for their wicking properties. In
It’s difficult to compare all fleeces to all wools for their wicking properties. In general, a synthetic fleece with short lengthwise fibers wicks the best, slightly edging out merino wool. Fleece base layers use these short fibers to create a capillary action to wick sweat away from the skin. Merino wool, however, contains natural antimicrobial properties which will keep your sweaty base layers from stinking. So if your adventures take you off the grid for multiple days, you may prefer merino over synthetic fleece, while if you’re more of a daily runner, then synthetic might be preferable
We have many more choices in textiles now than we once did—and in just about all realms of life—thanks to technology. Performance clothing is but one example. When it comes to deciding what to wear to keep warm in cool weather, we must no longer settle for clothing that meets some of our needs but not others. Just like ‘there’s a tool for every job,’ there is a warm clothing layer—in wool or fleece— for every environment.
Frequently Asked Questions
Which is better—fleece or sherpa?
Neither is better than the other—whether you lean towards fleece or sherpa depends upon your personal preference, and how the fabric is used to create the garment in question. Sherpa is actually a type of fleece, and looks a little like sheepskin, smooth on one side and with a lofty pile on the other. You’ll most often see it used as a lining in a garment instead of as its primary fabric, owing to its exceptional softness. Fleece, on the other hand, can describe any textile, natural or synthetic, that’s brushed on one side. While fleece can serve as the sole fabric in a garment, polyester fleece is typically not as soft next to the skin as sherpa. Both fabrics offer warmth and comfort on chilly days.
Does fleece shrink?
No, most fleece made from synthetic fiber will not shrink much at all in the washer or the dryer, but the specific type of synthetic fabric used to make the fleece can be slightly more or less prone to shrinkage. Polyethylene terephthalate (PET) describes most fleece and is far less likely to shrink than other synthetic fibers. Fleece made of cotton or a cotton blend can shrink in the wash or drying cycle—always follow the washing instructions on the manufacturer’s label. Note that drying polyester fleece on high heat (at 180°F or higher) can permanently damage the fabric.
Does fleece absorb water?
No, most polyester fleeces will not absorb water, and thus are less likely than other textiles to absorb odors. If a fleece garment does absorb water, unlike wool, it will not continue to insulate the wearer. But if it is a two-ply garment, the inner layer is likely to remain dry. Notably, saturated fleece dries much faster than saturated wool.
Can wool get wet?
Yes, wool can get wet, and water will not hurt it—not surprising given its origins as the warm, insulating layer on sheep and similar types of mammals. If you’re caught in a downpour wearing a wool sweater, it’ll still keep you warm, while it naturally repels the water. But if your wool garment gets wet, take care to avoid machine drying it, which will cause it to shrink. Instead, reshape and dry it flat, or roll it up inside a towel to dry.
Is wool breathable?
Yes, wool is naturally breathable. This is one character trait among many that make wool an attractive fabric to use in base layers and other performance clothing.