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Forced Air Cooling

As the weather gets hotter, it is helpful to improve your knowledge of how best to cool your home. And the more you understand about how your cooling system works, the better you can keep it running when you need it most.

What is forced air cooling?

The main two types of central heating and cooling systems available are forced air and hydronic. Forced air, which uses air as its heating and cooling transfer medium, is the most commonly used type in the United States. Hydronic (sometimes referred to as radiant), which uses water as the transfer medium for heating and cooling, is more commonly used in Europe.

A forced air system relies on ductwork, vents, and plenums to distribute heated or cooled air, which it pulls from separate heating and air conditioning systems. So, it is important to note that when it comes to determining what type of cooling system you want, you are not choosing between forced air and central air, because central air is the cooling system within the forced air system. Rather, you would be choosing between forced air, hydronic, or a window air conditioning unit.

How does forced air cooling work?

To better understand a forced air system, it is important to know what the following components are:

  • Air handler—This device regulates and circulates the air for the system. Usually a large metal box, it houses a blower, cooling and/or heating elements, and several other components. The air handler connects to the ductwork system, which both distributes the conditioned air throughout the building and also returns the air to the handler so the cycle can continue.
  • Supply plenum—The supply plenum is a box attached to the supply outlet of the HVAC equipment, through which the blower pushes hot or cold air to be distributed throughout the ductwork.
  • Return plenum—This box collects the returning or “used” air that is sucked back into the return ducts to be recycled for another round of heating or cooling. Return plenums often have air filters.

To cool your house, your forced air system uses your thermostat to communicate with your central air conditioning system. So, when the warm air inside your home comes into contact with the indoor evaporator coil of the central air system, the heat energy transfers to the refrigerant located inside the coil. That transmission cools the warm air, and the refrigerant is then pumped back to the compressor for the cycle to restart. Central air systems use an outdoor condenser to deliver chilled refrigerants through the system’s coils. The forced air system then uses these coils to cool the air before circulating the cold air throughout your home.

Note that while the heating element that a forced air system uses may be fueled by electricity or gas, the central air system relies on electricity.

What are the pros and cons of forced air cooling?

While forced air cooling systems have a lot of advantages, it is always good to consider both the positive and negative traits of the system.


  • Provides quality air and comfort—By using air filters, the system can trap allergens and other airborne particles that can cause breathing difficulties or sickness. You can also add dehumidifier or humidifier units to your forced air system to maintain a comfortable humidity level in your home without needing to use excessive amounts of energy.
  • Energy efficient—Government regulation requires that new forced air systems be designed to operate at high efficiency levels. So, today’s systems cool and heat your home more efficiently, which can save you money on your gas and electric bills over the years.
  • Responds better to programmable thermostats—Forced air cooling systems respond quicker than hydronic systems to thermostat signals, which increases the system’s efficiency and your comfort. Programmable thermostats are another great way to save money on your bills, because you can choose different temperature settings for various times of day. For example, if no one is home during the day, you can set the thermostat to a higher temperature while you are gone and only lower it when you will be home.
  • Combines heating and cooling—This type of HVAC system is the only one to combine cooling and heating, so the same ductwork works for both your furnace and your central air units.


  • May distribute air unevenly—Because forced air systems rely on ducts and vents, the air flow can be affected if any ducts or vents are obstructed. Sometimes this can be easily fixed, such as when a piece of furniture is covering a vent. However, if a room has a poorly located or too small vent, this issue can be harder to resolve.
  • May create an unhealthy environment—While the system is created to remove harmful things from the air with the use of filters, it relies on being properly maintained. So, if you do not regularly replace the filters, the system can actually spread the very particles it is designed to filter out.
  • May be noisy—Every time the system starts up, you will hear the fans turn on (some units emit a clunking sound) and the air flow through the vents. This may affect your ability to sleep or focus on certain tasks.

Three questions to consider before installing a forced air cooling system

If the pros of a forced air cooling system outweigh the cons for you, it is still worth considering these three questions before you spend your money:

  • What type of heating system does your house have? If your house already has a forced air heating system, then adding a forced air cooling system should be fairly easy and will likely be the least expensive option. If you do not already have ductwork in place, you can still add a forced air cooling system, it will just be a longer, harder, and more expensive process.
  • What type of air conditioning unit is best for you and your house? The more efficient an A/C unit is, the more expensive it will be. So, while it will save you more money over time, you will need to determine whether you can afford the upfront costs. Sometimes, it is more cost effective to go with a mid-range unit, especially if you live in a location where you only need to run the A/C a few months out of the year. Consult a professional HVAC contractor whom you trust to find out what air conditioning unit has the best capacity to cool your home efficiently.
  • What can your circuit breaker box handle? Your electrical panel must have the space to add a dedicated breaker for your air conditioner. If it does not, you will have to upgrade your electrical panel, which usually requires hiring a professional electrician.

Typically, adding a forced air cooling system to a new(er) house is a simple task, even if you have to set up the entire forced air system from scratch. Older houses, on the other hand, can pose more problems if they do not already have the ductwork in place or their electric panels have not been updated. So, if you are considering adding forced air cooling to an older home, it is wise to consult a trustworthy HVAC professional who can better outline the best way to proceed with your particular house.

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