Global Air Handlers Market By Type (by Products, HVAC Air Handler?, Central Air Handler?, Others, by Components, Filters, Heating /Cooling Elements, Humidifier, Blower/Fan, Heat Recovery Device, and Others), By Application (Residential, Hospitals, Universities, Laboratories, Office Ventilation, Hotels, and Others), By Region, and Key Companies - Industry Segment Outlook, Market Assessment, Competition Scenario, Trends and Forecast 2020-2029