In this article, we report on an experimental investigation of the thermal insulation and moisture vapor resistance of a thermal insulation assembly consisting of polyester battings and metal-coated thin nonwoven interlayers. Because of the blocking of radiation by the coated metal nanoparticles, the thermal radiative conductivity of the interlayer decreased from 0.0249 to 0.0194 W/m K after coating. We found that the thermal insulation of the fibrous assembly could be greatly improved without any significant effect on the moisture transfer through the incorporation of metal-coated interlayers between the fibrous battings in appropriate patterns. The thermal resistance of the assembly increased gradually with increasing number of incorporated interlayers until it reached a plateau. The presence of more metal-coated interlayers closer to the hot (heat-source) side was beneficial to higher thermal insulation. The moisture vapor resistance of the assembly showed no significant changes with increasing number of interlayers. The incorporation of three interlayers showed the best thermal insulation properties with little effect on the moisture transmission. This kind of thermal insulation assembly will have significant advantages in cold-protective clothing because of its high insulation properties and breathability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40205.