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 or 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
There are some confusing terms when comparing fleece and wool. Sometime’s 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 use of the term “wool fleece” is used for 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, of course, 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. However, 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?
Since warmth originates with the heat of your body, a better way to ask 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 it contains 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 Each
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:
- 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 the dryer on too high of a heat
- Can pill over time
- Insulates when wet
- Flame retardant
- Naturally anti-microbial (resists stink)
- High Maintenance
- Shrinks if washed and dried incorrectly
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 the modern world than we used to—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 occasion.