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Types of Synthetic Insulation

Almost everyone has somewhere in their closet a piece of synthetic insulated gear, but what is the difference between the Thinsulate in your gloves, the Primaloft in your jacket, and the Polarguard in the sleeping bag you want to buy? The array of synthetic insulation choices out there can be a bit dizzying at times, so we are here to provide a breakdown of the most common types and their primary uses.

Generally, it is worth keeping in mind that warmth is really a function of trapped air space. So, while some materials insulate more efficiently than others, it is really loft that makes the big difference in how warm a garment or sleeping bag is. Many articles provide a good gauge of the thickness of their insulation by putting a gram-weight number right on the tag, like “15D 33g PrimaLoft ThermoBall” in The North Face Thermoball Jackets. That number refers to the weight in grams of one square meter of the insulation. So, thicker, warmer insulation will weigh more per square meter and hence have a higher number. As a guide, 60 g is on the thinner, lighter end of the insulation scale. 100g is standard for mid-weight insulated jackets, and 150+g thicknesses can be found in really warm jackets.

In addition to trapping air, insulation works by reflecting the body’s radiated heat, preventing it from escaping into the environment. Reflective barriers (like silvery hanging liners inside some jackets) work way better than synthetic insulations for this type of heat loss, but every once in a while you will see this function brought up on a manufacturer’s hang tag.


Primaloft is highly compressible, very soft, and feels a lot more down-like than any other synthetic insulation. It also has remarkable water-resistance properties. The principle drawbacks to Primaloft are durability and price. Because of its short fibers, Primaloft is more prone to bunching and sees limited use in sleeping bags. While it is still cheaper than down, it is at the top of the price range for synthetics. There are a few varieties of Primaloft, but the most commonly seen are Primaloft Sport, the value option, and the higher-end Primaloft One, which features finer fibers and more water resistance. The newest material from Primaloft is called Infinity, and it is Primaloft’s entry into the continuous filament field. Look for it to compete against Polarguard Delta in sleeping bags.

Proprietary Insulation:

It is worth it to mention that in addition to these brand-name materials, many outdoor brands complicate things further by using their own proprietary insulation in lower price point items. Here are a few of the common names in case you come across them on a hangtag and want more info:

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