The short answer: PrimaLoft offers the best warmth-to-weight and compressibility (closest to down), Thinsulate is a thin, durable, cost-effective insulator strong in gloves and boots, and Coreloft is Arc’teryx’s proprietary mid-range synthetic balancing warmth and loft retention. All three are synthetic fills that stay warm when wet — their differences are in weight, packability, durability, and price.
For B2B buyers building insulated jackets, the fill brand is both a performance choice and a marketing claim. As a factory that sources and sews all three classes of synthetic insulation, here’s how they actually differ on the cutting table. (For the synthetic-vs-down decision, see our synthetic vs down guide.)
Synthetic Insulation in One Sentence
Synthetic insulation traps warmth with fine polyester fibers that mimic down’s loft but keep insulating when wet — PrimaLoft, Thinsulate, and Coreloft are the three best-known brand families.
PrimaLoft
Developed originally for the US military as a down alternative, PrimaLoft is the premium synthetic benchmark.
- ✅ Best warmth-to-weight of the three (PrimaLoft Gold rivals 550-600 fill down)
- ✅ Highly compressible and packable
- ✅ Water-resistant, retains most warmth when wet
- ❌ Highest cost
- Used in: premium jackets, technical mid-layers
PrimaLoft comes in tiers (Gold, Silver, Black, Eco with recycled content) — specify the tier, not just “PrimaLoft.”
Thinsulate
A 3M brand, Thinsulate uses ultra-fine fibers to insulate in a thin, dense layer without bulk.
- ✅ Excellent warmth in thin profiles
- ✅ Durable, holds up to compression cycles
- ✅ Cost-effective
- ❌ Less compressible/lofty than PrimaLoft
- Used in: gloves, boots, workwear, structured jackets
Thinsulate is rated by gram weight (40g, 100g, 200g/m²) — higher = warmer.
Coreloft
Arc’teryx’s proprietary synthetic, Coreloft is a mid-range balanced insulator engineered for loft retention.
- ✅ Good warmth-to-weight, holds loft well over time
- ✅ Resilient to compression
- ❌ Proprietary (Arc’teryx) — limited general sourcing; usually spec’d as “Coreloft-equivalent”
- Used in: Arc’teryx insulated jackets
For most B2B programs, Coreloft itself isn’t openly sourced — buyers spec a “Coreloft-class” synthetic with similar loft and resilience.
Side-by-Side Comparison
| Property | PrimaLoft | Thinsulate | Coreloft |
|---|---|---|---|
| Warmth-to-weight | Highest | Moderate | High |
| Compressibility | Excellent | Lower | Good |
| Wet warmth | Excellent | Good | Good |
| Durability | Good | Excellent | Good |
| Profile | Lofty | Thin/dense | Lofty |
| Relative cost | $$$ | $ | $$ (proprietary) |
| Best use | Premium packable | Gloves/workwear | Mid-range jackets |
How They Compare to Down
All three stay warm when wet — down’s biggest weakness — but down still wins on warmth-to-weight at high fill powers. Synthetic is the choice for wet climates, budget lines, and animal-free programs. See fleece vs down for the insulation-layer overview.
Which Should You Spec?
| If your jacket needs… | Spec… |
|---|---|
| Premium packable warmth | PrimaLoft Gold |
| Thin warmth (gloves, structured) | Thinsulate |
| Recycled/eco claim | PrimaLoft Eco |
| Budget insulated jacket | Thinsulate or generic poly |
| Arc’teryx-class performance | Coreloft-equivalent |
Specifying Insulation as a B2B Buyer
Define: brand and tier (e.g., “PrimaLoft Gold” not just “PrimaLoft”), fill weight in g/m² (60g/100g/133g/200g), placement (full vs body-only mapping), and whether you need a recycled-content version for sustainability claims. The common mistake is naming a premium brand but a low fill weight — the hangtag impresses, but the jacket isn’t warm.
Frequently Asked Questions
Is PrimaLoft warmer than Thinsulate?
Per unit of weight, yes — PrimaLoft Gold offers better warmth-to-weight and packs down smaller. Thinsulate provides excellent warmth in a thin, durable profile, which is why it dominates gloves and boots, but it’s less lofty and compressible than PrimaLoft.
Does synthetic insulation work when wet?
Yes — that’s its main advantage over down. PrimaLoft, Thinsulate, and Coreloft all retain most of their insulating value when damp and dry faster than down, making them the safer choice for wet climates and high-sweat activity.
What fill weight of insulation do I need?
For mild conditions, 40–60 g/m² is enough; 100–133 g/m² suits cold weather; 200 g/m²+ is for extreme cold. Fill weight matters as much as the brand — a premium fill at low weight won’t be warm.
What MOQ is needed for custom insulated jackets?
At PT Outwear, custom insulated jackets start at a 30-piece MOQ with 1-piece sampling, so you can confirm the warmth of a chosen fill and weight on a real sample before scaling production.
Spec the Right Fill With an Insulated-Jacket Factory
Synthetic insulation is a performance choice and a marketing claim at once — but only if the brand and fill weight match the conditions. At PT Outwear we source and sew PrimaLoft, Thinsulate, and equivalent synthetics into custom insulated and softshell jackets from 30-piece MOQ with 1-piece sampling. Our OEM manufacturing team can recommend the right fill and weight for your target climate and price.
Related Technical Fabric Guides
PrimaLoft Grades and Other Synthetic Insulations
What is PrimaLoft, exactly?
PrimaLoft is a brand of synthetic insulation built from ultra-fine polyester microfibres engineered to imitate the structure of down. It was originally developed for the US Army as a down replacement that keeps working when wet. The fibres are treated to be water-repellent, so unlike down the insulation retains most of its loft — and therefore most of its warmth — after soaking. It is sold as batting to garment manufacturers rather than as a finished product, which is why it appears inside jackets from many unrelated brands.
PrimaLoft Gold, Silver and Black — what the grades mean
The grades are tiers of warmth-to-weight performance, not different materials. Gold is the top tier, with the finest fibres and the highest warmth per gram, and is used where weight matters most. Silver sits in the middle and is the usual choice for general outdoor and commercial programs, balancing performance against cost. Black is the entry tier, heavier for the same warmth but substantially cheaper, and is common in lifestyle and workwear outerwear. Within each tier there are sub-variants — versions using recycled content, versions optimised for compressibility, versions blended with down — so ask for the exact product name rather than only the colour tier when specifying.
Is there a PrimaLoft Silver temperature rating?
No, and any supplier quoting one is inventing it. PrimaLoft does not publish temperature ratings by grade, for a sound reason: warmth is driven by fill weight in grams per square metre, not by grade alone. A 200gsm Silver garment is warmer than a 60gsm Gold garment despite the lower grade. Grade tells you the warmth-to-weight efficiency; fill weight tells you the total warmth. Specify both, and treat any temperature claim as an estimate that also depends on the shell fabric, fit, wind exposure and the wearer’s activity level.
How warm is 100g PrimaLoft?
The 100g figure means 100 grams of insulation per square metre of garment area, and it is the most common mid-weight specification in outerwear. As a working guide, 40-60gsm suits cool conditions and high-output activity where you would otherwise overheat; 100-133gsm covers general winter wear around freezing for someone moving; and 170-200gsm and above is for cold, largely static use such as spectating or standing work. These bands assume a windproof shell over the insulation — the same fill weight in an unlined, air-permeable garment performs far worse.
Is PrimaLoft waterproof?
No. PrimaLoft fibres are hydrophobic and water-repellent, which is a different claim: the insulation resists absorbing water and keeps most of its loft when damp, but water passes straight through it. Waterproofing is the job of the shell fabric and its membrane, seam sealing and DWR finish. This is why an insulated jacket specification always has two independent halves — the insulation for warmth and the shell for weather protection — and why a jacket with excellent insulation can still leave the wearer soaked if the shell is under-specified.
PrimaLoft vs Gore-Tex — a category confusion
These are not competing products and cannot be compared directly. PrimaLoft is insulation: batting that sits inside a garment and traps air to retain body heat. GORE-TEX is a waterproof breathable membrane: a laminate in the shell fabric that keeps rain out while letting vapour escape. A single jacket can and often does contain both. If you are comparing them, the question you actually need answered is usually whether you need warmth or weather protection — and for winter outerwear the answer is normally both, specified separately.
Coreloft insulation explained
Coreloft is Arc’teryx’s proprietary synthetic insulation, made from crimped multi-denier polyester staple fibres. Mixing fibre diameters is what gives it its character: the finer fibres trap air efficiently while the coarser ones hold loft under compression and resist packing out over time. It is a like-for-like alternative to PrimaLoft in the same jackets, and since it is proprietary it appears only in Arc’teryx garments. Coreloft Continuous is the sheet form, which resists shifting and migration better than loose batting in high-movement garments.
Climashield and LIFALOFT compared to PrimaLoft
Climashield, most often seen as Climashield APEX, is a continuous-filament insulation rather than a short-staple one. Because the filaments run continuously through the batt, it does not need quilting to stay in place and will not migrate or clump, which makes it the standard choice for ultralight quilts and for gear that must survive repeated compression. It is heavier than top-tier PrimaLoft for equal warmth but far more durable over years of packing. LIFALOFT is a PrimaLoft collaboration developed with Helly Hansen, combining PrimaLoft fibres with Helly Hansen’s Lifa fibre to cut weight while keeping loft; it behaves like a PrimaLoft variant rather than a separate technology. For a manufacturing program, the practical distinction is that continuous-filament insulation lets you skip quilting lines while staple batting usually does not.
