1. A thermal appliance comprising:an enclosure;
a heating compartment within the enclosure; and
a fibrous insulating material disposed between the heating compartment and the enclosure;
wherein the fibrous insulating material comprises one or more layers; and
wherein a portion of at least one layer is compressed such that the compressed portion forms a channel in the fibrous insulating material to allow air flow in a space between the enclosure and the heating compartment.