Abstract: An air-conditioner system including a movable unit which is deployed in the space to be heated or cooled by the system. The movable unit has a first heat exchanging apparatus, a second heat exchanging apparatus, a compressor, a fan operatively associated with said second heat exchanging apparatus, and a liquid source of either hot or cold liquid, the first heat exchanging apparatus being in heat exchanging relationship with the liquid source. An accessory heating element such as a heating coil is provided for heating liquid supplied to the liquid source. During enclosure cooling the first heat exchanging apparatus serves as a condenser, and during enclosure heating as an evaporator, and vice-versa for the second heat exchanging apparatus. A liquid supply system exterior of the enclosure provides liquid to the liquid source.