What HVAC component is primarily responsible for generating heat?

The furnace or heat exchanger is primarily responsible for generating heat in an HVAC system. This component works by burning fuel, such as natural gas, oil, or propane, or through electrical resistance to produce heat. The heat generated is then distributed throughout the building via ducts and air handlers, ensuring that the indoor spaces reach the desired temperature.

In the context of HVAC systems, the air handler's role is to circulate the air but not to generate heat itself; it simply moves the heated air produced by the furnace. The condenser is part of the cooling cycle and is responsible for dissipating heat from the refrigerant, while the evaporator coil absorbs heat from the air to help cool the indoor environment. Thus, while all these components are essential for the overall operation of an HVAC system, it is the furnace or heat exchanger that is specifically tasked with generating heat.