Thermolite
Invista engineered hollow-core polyester fiber designed for lightweight insulation. Used as fill or in fabric blends for cold-weather activewear.
Material Score Breakdown
7-axis material rubric, not a garment verdict — see disclosure below.
How long the fabric lasts with regular use
Softness, feel against skin, wearability
Air flow and ventilation
Heat retention and insulation
Ability to pull sweat away from skin
Environmental impact of production and disposal
How easy it is to wash, dry, and maintain
Products with thermolite
We don't have any garments containing thermolite in our catalog yet. Browse the full synthetic materials or check the product catalog.
What this score doesn't measure
This is a material rating, not a verdict on any specific garment made from thermolite. The axes above are research-backed averages for the fiber itself.
- ×Construction. Yarn staple length, weave / knit structure, stitch count, finishing. Identical fiber, very different garments.
- ×Fabric weight (GSM). A 140 GSM tee and a 220 GSM tee made of the same thermolite feel and last very differently.
- ×Dye + finishing chemicals. Beyond the three we flag (PFAS, formaldehyde, antimony), dozens of textile finishes aren't modelled.
Best For
Excellent warmth (85) and durability (75) for cold weather
Excellent durability (75) and comfort (65) for office wear
Good comfort (65) and care ease (78) for casual wear
Good moisture wicking (70) and durability (75) for weather protection
Good durability (75) and breathability (50) for outdoor activities
Detailed Use Case Scores
Pros
- ✓ Excellent warmth without bulk
- ✓ Lightweight hollow-core fibers trap air efficiently
- ✓ Retains insulating ability when wet
- ✓ Quick-drying compared to down
Cons
- ✗ Petroleum-based and not biodegradable
- ✗ Less warm per gram than down
- ✗ Can compress and lose loft over time
- ✗ Limited breathability
Better alternatives
Higher-scored synthetic materials. Same category — what to consider instead.
+12 vs Thermolite · 76/100
Membrane technology that is waterproof yet breathable. A laminate applied to other fabrics rather than a fabric itself.
+11 vs Thermolite · 75/100
Ultra-high-molecular-weight polyethylene (UHMWPE) fiber — the world's strongest fiber by weight. 15x stronger than steel, used in cut-resistant gear, ultralight backpacks, and high-performance sails.
+10 vs Thermolite · 74/100
Waterproof breathable membrane fabric (Gore-Tex, eVent, or similar technology) laminated to a face fabric. The gold standard for rain and storm protection in technical outerwear.
Care Guide
Special Notes
• Machine washable — retains insulation when wet
• Tumble dry low
Additional Care Tips
- • Machine wash cold (30°C/85°F) on gentle cycle with mild detergent
- • Tumble dry on low heat — some heat helps restore loft in hollow-core fibers
- • No ironing needed — Thermolite insulation does not wrinkle
- • Avoid fabric softener and bleach which degrade the hollow-core fiber structure
- • Store uncompressed when possible to maintain insulation loft over time
- • Follow garment manufacturer guidelines — Thermolite is usually part of a layered construction
Cost
$$$$$
Mid-range
Shrinkage
Won't shrink with normal washing
Eco Rating
High environmental impact