HVAC (Heating, Ventilation, and Air Conditioning) tag is used for questions about ventilation systems which may also heat or cool the air moved. This tag should be used with questions about the monitoring and control of the devices that are part of a ventilation system as well as as the devices that monitor and control the quality and characteristics of the air, air quality. Typical use of IoT devices is to allow for remote monitoring of an HVAC system.
HVAC systems are a necessary part of liveable buildings and vehicles as its "goal is to provide thermal comfort and acceptable indoor air quality."
A basic HVAC system is one whose design is a way for the air in a structure to move either through mechanical means such as fans or non-mechanical due to the design of the structure or vehicle.
In order to provide a comfortable temperature the air may be heated or cooled. The humidity of the air is also a consideration for comfort so either humidifiers or dehumidifiers may be used to adjust air humidity.
Most questions concerning HVAC for IoT applications involve remote monitoring of equipment and air characteristics (temperature and humidity). IoT is typically not a consideration for the actual equipment used to build an HVAC system (fans, fan controllers, chillers, thermostats, etc.).