Primaloft vs Coreloft vs Down: Quick CLO Cheatsheet

What is a CLO?

CLO value is an important factor in determining a synthetic jacket’s warmth. Metaphorically, like FP * FW value in down jackets…And the higher the value is, the warmer the insulation is.

Synthetic insulators provide more insulation per thickness. This is why any insulation can achieve desired CLO value after setting the right amount of thickness. But of course, your jacket will become heavier in the end.

Manufacturers rarely share the CLO values of their products. Let's say they disclosed these values; which standard did they use to measure them? To correctly be able to compare them, this info is also crucial.

Against all odds, I combed through the CLO values of synthetic insulators. And, to give you some ideas about jackets' warmth, I've prepared a detailed table.

But, I'd like to point out that I got the values from forums like Reddit and producers' technical data sheets and catalogs. That is, they aren't based on scientific investigations and aren't totally reliable.

In the table, you'll see some calculations related to synthetic insulated jackets. For example, the Patagonia Nano Puff Hoody contains the Primaloft Gold Eco having 0.92 clo/oz/yd². And the jacket's insulation amount is 1.77 oz/yd². So,

Calculated CLO of Patagonia Nano Puff Hoody = 0.92 x 1.77 = 1.63

As I said earlier, some jackets have different insulation weights on various parts. So, I calculated the CLO values considering the percentage of their body surface area covered [2].

Sources: Richard Nisley's "A Revised Paradigm for Understanding Garment Comfort Limits" paper, Hohenstein Institute's Primaloft Thermal Performance paper and Primaloft's own fact sheets (Gold Eco, Silver, Black). 

Takeaway: CLO differences between synthetic insulators per unit mass are almost non-existent. 

Read more: 

• https://outdoorcrunch.com/synthetic-insulated-jackets/
• https://outdoorcrunch.com/jackets/

Other factors, especially insulation amount, is a much more decisive in determining the end warmth. 

This is not to say that these values are completely useless. It's just that looking at the clo/oz/yd^2 value of a garment (in our case, jackets) alone won't give you the conclusion you need.

There are other things you need to take into account. Such as insulation amount, insulation distribution, insulation thickness, the fit and length of the jacket, etc. 

• Primaloft Gold (aka Primaloft One) is developed by Primaloft and partnered by many brands such as Patagonia, Moncler, and Adidas. 
• ThermoBall is developed by The North Face.
• PlumaFill is developed by Patagonia.
• Coreloft is developed by Arc'teryx.

You can find the table below pretty useful. 

Synthetic Insulations

Synthetic insulators are typically designed to mimic down's properties.

Ultra-fine fibers in their structure create heat-trapping air pockets, keeping your body heat... though not as good as natural fillings [1].

But, when it comes to water resistance, they don't collapse and lose their insulating power when wet, unlike down jackets. Also, their drying time is shorter.

So, I'd say synthetic insulated jackets might be good choices for damp conditions or high-output activities. And, you can clean them easier than those with down.

Plus, they're more affordable and hypoallergenic. But still, keep in mind that synthetic jackets are less packable and heavier than down ones.

How Warm Are Synthetic Insulated Jackets?

Truth be told, it's pretty tough to tell how warm a synthetic insulated jacket is.

For a start, I'd say you'll need more synthetic insulation than natural down to achieve the same warmth. It means your ultra-warm synthetic jacket will likely be heavier than its down counterpart.

Of course, you'll want to wear lightweight synthetic jackets during high-intensity activities. To offset the weight, some brands use lighter insulations in their jackets, like 40 g/m². Or only in the jacket's sleeves, hood, and neck.

These active insulation jackets sacrifice a little warmth but still can work great trapping air. Also, they're remarkably breathable. My best picks in this category are Arc'teryx Proton LT and Patagonia Nano-Air.

Synthetic Insulation Types

There are three major categories of nonwoven insulations: Short-staple, continuous filament, and cluster fiber. Also, it's possible to knit synthetic insulations.

Non-woven Insulations

Short-staple insulation

These insulators feature densely packed short fibers to trap air and keep your body heat. But, the fibers can move around and form cold spots.

Short-staple fillings provide a soft feeling. They're compressible and have good warmth-to-weight performance. But, they can lose their insulating ability faster than other synthetic ones. Meaning that you might need a new jacket after a while.

PrimaLoft, Arc'teryx Coreloft Compact, and Thinsulate are examples of short-staple insulation.

Continuous filament insulation

These insulations are made from continuous filament fibers.

They’re stiffer and less packable than short-staple insulators. But, their web structure is more durable and retains loft longer.

Climashield, Coreloft Continuous, and PlumaFill are at the forefront of the market.

Cluster fiber insulation

There are small fiber tufts in this insulation type. They're designed for closely mimicking down to minimize heat loss.

The North Face ThermoBall Eco and Freudenberg comfortemp are examples.

Knitted Insulations

These insulations don't need to be quilted because they're self-supporting knitted structures. So, the jacket's outer layer doesn't have to be high-density to keep the insulation.

After all, the jackets with knitted insulators are highly breathable. That’s why they're convenient for high-output activities.

But, to put it bluntly, they won't offer excellent insulation performance.

Polartec, Octa Loft, and Pontetorto are well-known knit insulations.

What Kind of Synthetic Insulation is Best for You?

This might come self serving but I think the best place to look at for this is the Typical Buyer Profiles section of this guide: https://outdoorcrunch.com/synthetic-insulated-jackets/.

PrimaLoft

PrimaLoft is a well-known brand in short-staple insulation. It has three main categories: Gold, Silver, and Black.

And they've tons of subcategories...

PrimaLoft Gold insulators have the highest CLO values among others. And that way, they might maintain your warmth even in harsh weather.

Generally speaking, PrimaLoft Silver ones display slightly worse insulation performance. So I'd say they'll be appropriate for wearing in a little warmer climates

And the PrimaLoft Black is the most basic insulation. You can opt for a jacket with this insulation for everyday use.

PrimaLoft also designs insulators in collaboration with some outdoor clothing brands. LifaLoft (Helly Hansen) and ThermoBall Eco (The North Face) are some of them.

By the way, I'd like to say I have been impressed with PrimaLoft's cross-core technology. The aerogel used could enhance your warmth without increasing your jacket's weight. Patagonia DAS Parka is an example.

Climashield

Climashield produces continuous fiber insulations made of long and hollow fibers.

Filaments in their structure allow recovery after applying forces during stretching or washing. So, they might help maintain the insulation performance of your jacket for a long time.

The company has a wide variety of insulations like Climashield Apex, Contur, Prism…

Each insulation has a prominent characteristic. For example, Climashield Apex is touted as lightweight warmth. And Climashield Prism is a high-performance insulation material produced using AquaBan technology. So, it can repel water effectively.

Speaking of which, Arc'teryx ThermaTek is thought to be a rebrand of Climashield Prism.

Coreloft

Coreloft is synthetic insulation used exclusively by Arc'teryx. There are two kinds of this insulation: Coreloft Compact and Coreloft Continuous.

The Coreloft Compact is thought to be a rebrand of Thermore Classic. And the Coreloft Continuous is of Climashield APEX.

The Coreloft Compact is made of staple fibers in various sizes that are crimped to trap air for more warmth. It's compressible and soft but might lose loft faster because of short fibers.

As you might guess from its name, the Coreloft Continuous includes filament fibers in the structure. That’s why it features higher integrity and more durability. But you can compress it less. Also, I'd say this insulation has some limits on its weight. 

FullRange & PlumaFill

Exclusive to Patagonia, FullRange is a product of Toray Mills, Japan. This is why it’s believed to be a rebrand of Toray 3DeFX+.

FullRange, which is quite stretchy and breathable, includes multi-denier polyester fibers. For now, Patagonia uses this insulator only in Nano-Air products.

PlumaFill is another innovative synthetic insulation of Patagonia. Microfilaments in this insulator spiral a central fiber to mimic down very well. It’s pretty warm and compressible. You might want to check out this page for more info.

Conclusion

Your synthetic insulated jacket's warmth is mainly related to its insulation's CLO value. And the higher the value is, the warmer you feel.

But, companies infrequently share their products' CLO values. And finding them is a bit challenging and time-consuming.

So, I prepared a table with publicly available CLO values of synthetic insulators. And I added the calculated CLOs for synthetic jackets to the table. Also, you can find some details in the post about the common synthetic insulations in the market, like Primaloft, Climashield, etc.

I hope this information will help you when choosing a synthetic insulated jacket.

I recommend you also check out my other post, "Best Synthetic Insulated Jackets".