You can purchase the A/C unit and deduct from your next months rent under civil code article2694. Put your demand in writing and your intention to buy the unit and deduct from your rent.
Art. 2694. Lessee's right to make repairs
If the lessor fails to perform his obligation to make necessary repairs within a reasonable time after demand by the lessee, the lessee may cause them to be made. The lessee may demand immediate reimbursement of the amount expended for the repair or apply that amount to the payment of rent, but only to the extent that the repair was necessary and the expended amount was reasonable.
Answered on Sep 11th, 2016 at 8:00 AM