Heating, Ventilation, and Air Conditioning or HVAC systems as they are commonly known control buildings internal temperatures. An efficient HVAC system has two primary components the air conditioning system which cools air, and the furnace which heats it. They work in conjunction with one another in order to provide ideal air temperatures year round.
For the purposes of this website we will focus on how the furnace works in an HVAC system. The furnace runs in fall and winter months, when the ambient outside air temperature is too cold. The most common HVAC furnace is a forced air unit. Both heated and cooled air are pumped through the same ventilation network. Meaning cool air is pumped through the same ductwork in the summer that warm air is pump through in the winter. Forced air furnaces pull cold air in through the return air duct and through a filter. It enters the blower which uses a motor to blow it up into the combustion chamber that contains a heat exchanger. The heat exchanger contains hot coils that are heated via natural gas or electricity. The coils become slightly cooled by the contact with cold air and require a constant source of heat supplied by the burners. The cold air is blown over the hot coils which heat it to the desired temperature designated by the thermostat. The hot air is then blown through the supply plenum and pumped throughout the duct work. It exits via the supply registers directly into the room.