A cooling and heating system for seats and other user items utilizes a thermally conductive sheet with one or more thermoelectric devices. This thermally conductive sheet has high thermal conductivity and is flexible, and may comprise polyimide, graphite, PGS graphite, carbon fiber, or more advanced materials such as graphene or carbon nanotubes or other high thermal conductivity material such as copper or aluminum sheet or mesh. The thermally conductive flexible sheet with remote thermoelectric device provides good temperature uniformity across the seat, quick response time, and excellent performance in extreme ambient temperatures. The high thermal conductivity sheet can be placed in the seat area between the upholstery and seat cushion with thermoelectric devices thermally connected to the thermally conductive sheet away from the occupant seating area to provide comfortable and durable seating with thermal comfort control. Heat rejection may be accomplished using a heat sink (with or without a fan) or a heat pipe connected to a heat sink (with or without a fan) or other heat rejection mechanisms.