HVAC is an acronym for heating, ventilation and air conditioning. You are obviously aware of heaters or heating appliances, air conditioners, or air conditioning systems, and ventilators or ventilation systems. Imagine a large appliance that does all three. That would be an HVAC. However, you should not think of HVAC as one appliance that has three isolated or disassociated appliances. HVAC is one integrated unit that can heat your indoor air and circulate the warm air, cool the indoor air and facilitate ventilation.
If you were living up north where winters are freezing, you would focus more on the heating aspect of an HVAC. If you are living down south where summers are scorching and hot, you would focus on the air conditioning or cooling of an HVAC. In either case, you may want adequate ventilation. An HVAC is not a heater, cooler and ventilator, rolled into one.
Heating in HVAC
Typically, heaters are of two types. There are heat pumps that extract heat from outside and circulate it inside. The indoors are usually confined and sealed to prevent the warm air from leaking out. Heat pumps may have ducts, very similar to the ducks of an air conditioning system. Straight cool systems are the other type of heating appliances that work on electric heat. They have heat strips which are heated up using electricity. The same heat is then circulated throughout your room or home. Then there are the classic furnaces and fireplaces to heat the room. Heating in HVAC is different from these. Cool indoor air, during winters, is passed over a heating coil inside the HVAC and the warm air is then circulated back inside.
Ventilation in HVAC
A standard duct in a heating or air conditioning system will only circulate hot or cool air from the appliance to the confined indoors in your room, home, or office. Indoor air doesn’t get circulated outside or ventilated in the process. HVAC has ducts that serve the purpose of two-way circulation. An HVAC system has a ventilation or exhaust fan that extracts stale and contaminated air from the indoors. Some HVAC units have a separate system to draw in fresh air from outside and thereby ventilating the indoors by circulating that fresh air.
Air Conditioning in HVAC
HVAC is similar to a split or a centralized air conditioning system. There is an outdoor unit, which has the condenser, compressor, and other components. The indoor unit has the blower motor, evaporator coil and other sensors to let you manage the system. The ducts draw in the warm stale air from your room. The air is compressed and cooled, which is then circulated back through the ducts into your room, office, or home.
HVAC is one integrated unit which can heat or cool and cater to ventilation at all times.