A thermostat for HVAC (heating, ventilation and air conditioning) is an instrument used to regulate the temperature of a space such as a room or building. The thermostat works by monitoring the ambient environment and making adjustments based on user settings. This can be done manually, via an app-based system or remotely via an online interface. Thermostats are critical components of HVAC systems because they ensure the optimal performance of heating and cooling equipment. They also offer advantages such as energy savings and improved comfort levels.