Abstract: Embodiments described herein related generally to a multi-layer garment liner including an inner layer and an adjacent layer joined together around a periphery with a heat trapping space between the inner and adjacent layers. A plurality of inlet vents in the inner layer are configured to direct air from outside of the liner/garment into the heat trapping space. The inlet vents can be located in a lower part of the liner/garment. A plurality of outlet vents in the inner layer are configured to direct air from the heat trapping space to outside of the liner/garment. The outlet vents can be located in an upper part of the garment liner. The multi-layer garment liner can further include a plurality of elongate spacer strips located in the heat trapping space, the spacer strips arranged to direct an airflow from the inlet vents toward the outlet vents.