Flexotherm is a reflective vapour barrier. It works similar to traditional vapour barriers with the added benefit of also acting as a radiant heat barrier. Vapour barriers are designed to retard the passage of moisture as it migrated through a wall. Traditional mass insulation will absorb moisture - the vapour barrier protects your insulation helping it to work harder. The addition of the radiant heat barrier helps to keep your home warm in the winter since the barrier reflects 97% of radiant heat back into the room. Approximately 50% to 75% of heat loss in a home is due to radiant heat.