One possible reason that HVAC systems blows warm air is dirty filters. The system is producing cold air but it cannot flow through the ductwork. Clean air filters protect your equipment and help it perform properly. HVAC systems work harder as the outside ambient temperatures approach triple digits and may not cool as effectively as you desire.
You should also verify that the outside unit is running. If the outdoor unit is on, ensure that leaves and other debris are not obstructing the airflow. An air conditioner that blows warm air can be a sign of insufficient refrigerant. Only licensed air conditioning repair technicians can replenish HVAC coolant.
Give us a call today if your ac unit is blowing hot air where convection is preventing good cooling: 239-596-5855.