There is described an oxygen concentrator device (10 100a 100b), particularly for house oxygen treatment, comprising: a compressor (16) designed to compress a flow (A) of ambient air a molecular sieve battery (18) in fluid communication with said compressor (16), and designed to separate oxygen to be delivered to a patient from the flow (A) of compressed ambient air and means (21) for delivering to the patient the oxygen flow (02) leaving the molecular sieve battery (18), The concentrator device (10 100a 100b) further comprises refrigerating means (30 300) placed between the molecular sieve battery (18) and the oxygen delivering means (21), such that the oxygen flow (02) reaches the patient at the desired temperature.