For firefighter protective clothing, the thermal protective performance is of primary importance but its comfort should also be considered. In this aspect, the effects of the thermal barrier construction on the level of thermal protection were investigated. Various thermal barriers were prepared to maximize the thermal protection and comfort properties. Multilayer thermal barriers prepared from meta-aramid needle punched nonwovens of different thickness and number of layers with and without spacers were compared. The differences in their thermal insulation and comfort properties were evaluated using flame testing, bending length measurements and water vapor permeability. For thermal barriers, multi-layer construction with spacers exhibited higher thermal protective performance and lower bending rigidity.