Polartec® Alpha® vs PrimaLoft® Insulation: A Comparison

Polartec® Alpha® vs PrimaLoft® Insulation: A ComparisonPin

Insulated jackets are made to keep you warm in chilly weather. During the winter months this is all the more important. Down and other similarly-insulated jackets come in many different designs, styles and warmth levels.

Here on our site we have gone through several different types of winter and other lighter jackets that rely on insulation to keep you cozy when the temperatures drop.

These past few days we have focused on the importance of insulation and today we will continue with a comparison that features two very popular types of insulation, Polartec® Alpha® and PrimaLoft®.


1. The Importance of Insulation

Before we begin with the actual comparison, let’s first learn why insulation is important and how does it actually work.

The way an insulator used in clothing or outdoor gear works is by creating small air pockets in between the clusters – for example down – or its fibers. These small air pockets then store the heat that is generated by the body naturally when the garment is worn.

Therefore, insulation does not provide warmth on its own, but it helps maintain the heat of the body, which then keeps you warm.

There is no one type of insulation, not just when it comes to the type of material used, but also when it comes to the shape, size and performance.

We have explored several types of insulations in the past, such as Down, Wool, Fleece, ThermoBall, Thinsulate, as well as the two featured in today’s comparison.

As you can see, the options are many and include both natural and synthetic types.

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Natural insulators include down and wool, which work differently due to their composition but are two of the best at insulating during the cold months.

Synthetic insulators, on the other hand, come in many options, providing a lot more versatility in their performance and they are also created in certain ways to mitigate the issues that are common for natural insulators.

One such issue is the resistance to wet conditions, for which down is notoriously known because it is rendered completely useless when wet. Wool fares a bit better, but if it gets wet it takes forever to dry.

Enter synthetic insulators, which are typically made of polyester and are not just water-resistant, but also quick-drying and many of them are able to insulate even when wet.

Related: Down vs Synthetic Jacket: What’s the Difference? Which Insulation is Better?

Both of today’s insulations are synthetic and it’s now time to begin with today’s comparison.

2. Polartec® Alpha® Insulation

Made by Polartec®, Polartec® Alpha® is a synthetic insulation that is designed to not function solely for the purpose of keeping the body warm, but to also help with temperature regulation.

For that reason, Polartec® Alpha® is considered to provide active insulation.

To learn more, here is our in-depth review of Polartec® Alpha®.

The way it works is by allowing excess body heat to be released. In doing so, it ensures that you will not overheat while partaking in demanding sports or activities and remain dry and cool throughout.

On the other hand, it also helps keep you warm, of course, which is what makes it so versatile and suitable for a variety of weather conditions and temperatures, not solely limited to the colder months.

It was originally designed for the U.S Special Forces, because they required an insulating material that would be able to keep up with the challenging conditions they had to be in.

As such, Polartec® Alpha® is designed to be highly functional and practical, too, by being very compressible and also stretchy, moving as you move.

It is a hydrophobic, highly water-resistant insulation, able to keep you dry for a considerable amount of time, while also being quick-drying.

Another quality that bears mentioning is its composition. Polartec® Alpha® is actually a fabric, not a loose or padding type of insulation, as we are used to seeing. It is made of lofted knit fibers, which connect to a solid mesh core that helps keep the fibers in place and gives it an even performance throughout.

The mesh core and the knit fibers are the reason why this insulation works so well as a temperature regulator, as they are placed in such a way that not only allow for heat to get trapped, but to also escape, while at the same time allowing for some level of air flow to keep the temperature stable and comfortable.

Polartec® Alpha® is also very lightweight and highly durable.

3. PrimaLoft®

Renowned as the closer down-mimicking insulation, PrimaLoft® is a polyester insulator made from polyester microfiber. This composition of microfibers is what gives PrimaLoft® its ability to insulate.

The thin and soft micro fibers are made to resemble down’s filaments, which helps create many tiny air pockets that trap the heat generated from the body.

In its composition, PrimaLoft® is not a loose, cluster-like insulation. It is a shaped fluffy sheet, which allows for a considerable amount of moisture wicking and evaporation, making it one of the most breathable types of insulators available.

Because it is made of polyester, it is not prone to moisture issues as it has a low rate of adsorption. Even when it gets wet, it does not lose its ability to insulate.

In fact, it performs so well when wet that it is one of the main reasons for it being so popular and renowned.

PrimaLoft® Synthetic Insulation

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PrimaLoft® comes in different types, which include:

  • PrimaLoft Gold insulation – revered as being the best performing synthetic insulation available, PrimaLoft Gold is designed for highly active people and its main purpose is to be highly functional in wet weather, by retaining as much as 98% of its warmth.
  • PrimaLoft Gold Insulation Eco – extremely lightweight and packable, the Eco insulation is made from 55% recycled polyester, making it an environmentally friendly insulation. It performs similarly to the Gold insulation and is used by many of the environmentally-conscious brands, namely Patagonia.
  • PrimaLoft Silver Insulation – more affordable than the Gold insulation, Silver performs beautifully and comes in the Active variation, made for people who lead active livestyles, Down-blend, a mix of 60% down and 40% synthetic fibers by PrimaLoft, and the Eco insulation, which is made from 70% recycled content.
  • PrimaLoft Black Insulation – the most affordable of the options, PrimaLoft Black is made for everyday use and comes in three variations, Eco, Down blend and Hi-loft.


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4. Comparison: Polartec® Alpha® vs PrimaLoft®

Now that we got acquainted with both Polartec Alpha and PrimaLoft, it’s time to look at how they compare to each other.


In regards to warmth, both of these insulations work impressively. They insulate very well and are suitable for wear in mild and cold temperatures.

With that being said, PrimaLoft is the better of the two because of the PrimaLoft Gold, which is comparable to 550 fill-power down in its loft and ability to insulate, making it the best choice for those looking to buy a jacket that is made for winter wear.

Weather Resistance and Breathability

Once again, they are both highly water resistant and also quick drying. PrimaLoft Gold performs exceptionally well in this regard because it is made to insulate even when wet, as we mentioned previously.

When it comes to breathability, it’s Polartec Alpha that has the best performance as its temperature-regulating design helps the jacket breathe better and be more comfortable to wear during outdoor activities.

people walking on field in foggy weatherPin

Comfort and Wear

Regarding how comfortable an insulation is will largely depend on the jacket design and the fabrics used. Both PrimaLoft and Polartec Alpha are quite lightweight, making them two of the most comfortable insulations to wear in this regard.

However, Polartec Alpha, being a fabric, is designed in a way that makes it really comfortable to layer with.

This works in its favor as it is not an insulation made for very cold temperatures, thus its ability to layer easily with other garments makes it suitable for those who rely on layering rather than on insulation alone.


When it comes to durability, we will have to say that they are evenly matched on their own, looking at them as insulations alone.

As for which products made with these insulations will last longer, it will mainly depend on the quality of the fabrics and design, not so much as on the insulation alone.

5. Which One Is Better?

Both Polartec® Alpha® and PrimaLoft® are insulations that you really cannot go wrong with.

Polartec Alpha would be the better choice for those who want a lightweight and highly compressible jacket, able to breathe well and suitable for sportive wear.

It is comfortable, durable and its temperature-regulating quality is its main selling point.

On the other hand, if you need a jacket that will keep you warm in really cold weather, which is prone to rain and it requires an insulation that can ensure your safety against the elements, PrimaLoft provides several options that can meet your needs.


Last updated: July 2019

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