PropertyFiberglass InsulationPolyester InsulationMaterial CompositionMade from spun glass fibers (glass wool)Made from thermally bonded polyester fibersThermal PerformanceHigh insulation efficiency; common in R6–R8 rated ductsModerate to high insulation, suitable for R4.2–R6Density Range12–32 kg/m³100–750 g/m³Skin IrritationCan cause itchiness or irritation upon contactNon-irritating and safe to handle without glovesAcoustic PropertiesExcellent sound absorption capabilityGood sound absorption, less than fiberglassFire ResistanceInherently fire-resistant, rated A2 in many systemsGood fire behavior but depends on bonding agentsEnvironmental ImpactContains glass; not biodegradableRecyclable and more environmentally friendlyRecommended ApplicationCommercial HVAC systems with strict insulation needsResidential or light commercial systems; user-safe installs
