Forced air and central air are two common types of heating and cooling systems used in homes and buildings.
If you know the HVAC things well enough, you will see that these two terms are not quite the same when comparing head-to-head.
In this article, we’ll define forced air and central air and learn how these systems work together.
Now, let’s dive into a quick comparison!
Forced Air vs. Central Air
Forced air is usually referred to as an indoor heating system, which includes a furnace used to generate heat and force the heated air through ducts and vents into the rooms in your house/building. A central air conditioner is a separate unit usually located outside, which generates cool air, and delivers it to your home/building, oftentimes using the same forced-air system.
Let’s dive deeper into how these systems work!
How does a Forced-air system work?
The system consists of a furnace or heat pump that heats or cools the air, a blower motor that forces the air through a filter into a ductwork system that releases the conditioned air into the rooms.
The return ducts bring the cooler air back to the furnace or heat pump to be heated again, creating a cycle that maintains a comfortable temperature throughout the home or building.
How does Central Air work?
A central air conditioning system includes an indoor and outdoor unit (the air conditioner), using a compressor, condenser, evaporator, and refrigerant. The AC is responsible for removing heat from the air inside a building and releasing it outside. The compressor compresses a refrigerant gas, which then passes through a condenser coil to release heat, turning it into a liquid.
The liquid refrigerant then passes through an expansion valve, causing it to evaporate and absorb heat from the air, before passing through an evaporator coil.
The blower motor forces air over the cold evaporator coil, cooling and dehumidifying the air, which is then distributed throughout the building via ductwork (using the forced-air system with the furnace).
The warmer air in the building is drawn back to the air conditioner through return ducts, completing the cycle.
Which one should you choose?
Your furnace and air conditioning unit are both needed for an HVAC system. So yes, you need to have them both installed and working if you are living in a place that has a significant difference in seasonal temperature (hot summer and cold winter).
While the furnace provides heat during colder months, the air conditioning unit takes over during the summer to cool your home.
However, even when your AC is running, it still needs to use the furnace’s fan to circulate the cooled air throughout your home. The reason is that the blower (fan) is needed to force the air flowing in the ductwork system, which delivers air to rooms through the vents.
If you feel like your house is not cooled properly, you may need to call an HVAC expert to troubleshoot and repair your AC if needed.
Can you only install a Furnace in your forced-air system without an AC?
You can install a furnace without central air conditioning because a furnace is a heating system that can be used on its own or as part of a larger HVAC system that may include air conditioning. The furnace has the necessary components to function and deliver heated air throughout your home.
If you only need a heating system for your home (you may be living in an all-year-round cold place), you may install a furnace without an AC for your forced-air system.
However, if you later decide to add air conditioning, you can install a compatible air conditioning system that can work in conjunction with your furnace’s forced-air system.
Can you install only Central Air Conditioning without a Furnace or Heat Pump?
A central air conditioning system requires a furnace or another type of heating system to function properly. This is because central air conditioning relies on the furnace’s blower motor to circulate cool air throughout the home.
Without a furnace or another type of heating system to power the blower motor, central air conditioning cannot function properly. Therefore, it’s necessary to have a heating system in place when installing central air conditioning.
What if you only need a cooling system?
If you only need a cooling system, you can opt for a standalone air conditioning unit, such as a window air conditioner, or a ductless mini-split AC. These systems are not relying on the blower or even the ductwork system to function.
Window air conditioners can be installed in a window or through a hole in an exterior wall, while ductless mini-split systems can be installed in individual rooms or zones throughout the house without the need for ductwork.
Depending on the size, space, and budget, you may want to choose a ductless AC or a window AC.
The bottom line
So you have had a better understanding that the key difference between a forced air system and central air conditioning is that a forced air system can include both heating and cooling components. In contrast, central air conditioning only provides cooling, which works by using the ductwork from the forced-air system.
As a homeowner, you need to understand the needs for heating and cooling for your house. A forced air system may be ideal for those who live in areas with high humidity and need both heating and cooling or just heating.
It’s also recommended to consult with a professional HVAC contractor to determine the best options for your home and budget.