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.
