The main purpose of this master’s thesis is description of the current technology of compressed air production in the grounds of Třinecké Železárny, a.s. (TZ). Compressed air for companies in the TZ area is manufactured and distributed by company Energetika Třinec, a.s. (ET). The part of the thesis is the preparation and execution of measurement including evaluation of specific energy consumption for production of compressed air by compressors of ET company. In conclusion there is proposed the possibility of substitution of compressors including the economic evaluation.