It is offered the exact and simplified methods of calculation of the vertical air condenser. It is shown that condenser breakdown on zones of cooling, condensation and subcooling of a refrigerant, and also the account of influence of hydraulic resistance on condensation temperature allow to define optimum quantity of circuits. The exact method of calculation shows an inefficiency of condensers, which hydraulics resistance exceeds 2K. The simplified method of calculation is expedient for applying, if hydraulic resistance reduces temperature of condensation no more than on 2 С.