Higher fill power generally means the jacket will be warmer, and brands usually specify the fill power in their down coats. One coat on this list that has synthetic insulation is the , which is one of the least expensive coats on this list! Warmth: We prioritized coats that actually keep you warm, which means opting for those with high-quality insulation (down or synthetic), weather-resistant materials, and silhouettes that block drafts without feeling bulky.