What is Ductwork? 3 Ways Air Ducts are Essential for Home Comfort

Air Conditioning, Heating, Home, Indoor Air Quality

Because of your busy day-to-day activities, you might have never paid attention to those openings in your walls, ceiling, or floor, some are covered with metal grilles, and others are slatted with movable dampers. You vaguely remember your contractor was telling you about it after the AC or furnace installation, and how it helps your HVAC systems do their job of efficiently making the temperature in your home comfortable.

This is the ductwork, which homeowners typically disregard. This is not surprising at all since compared to the other powerful, intricate, and complex HVAC components, the ductwork is pretty low-key and low-maintenance. So, what is ductwork?

DP what is ductwork

You will find that your knowledge about duct work could mean the difference between using it properly and misusing it. 

We will now share with you how ductwork works and how it can potentially impact the indoor air quality of your home, the performance of your unit, and your monthly utility bills.

Why is Ductwork and Why is it Important?

There are three major reasons why you need to care for and maintain your ductwork:

  1. Proper airflow. The ductwork is responsible for maintaining the necessary air pressure inside your home. In general, they perform their job by taking in the existing air from the room and pulling it into the central heating or air conditioning system to be processed. Once the air has been heated or cooled, the ductwork completes the cycle by helping to distribute the processed air to different parts of the home.
  2. Better indoor air quality. The ductwork contributes to the overall indoor air quality of your home and protects the AC unit at the same time. As most ductwork comes with a filter, it traps the dust, dirt, and other harmful debris from your breathing space and prevents them from being recirculated into the system and subsequently gets expelled into the room. Without the ductwork, the unwanted particles could infiltrate the internal mechanisms of the AC and damage its parts. Worse, the toxins could be distributed to your family’s breathing space and cause health problems.
  3. Lower energy consumption. If you have an adequate number of air ducts that are properly maintained, there will be less air pressure that will circulate. This would limit the possibility of holes and leaks. These air leakages are energy-wasters that ultimately lead to greater energy consumption and higher utility bills.

There are four parts to ductwork: the grilles, the registers, the supply and return ductwork. Grilles (or grills) are permanent openings, only covered by wide-gapped grating, that allow the indoor air to move freely from the AC system and back to the living space. Registers have adjustable dampers or louvers through which the homeowner can adjust the flow of the air by either widening the gap or restricting it. Return ductwork, as the name implies, draws in the air from your home and carries it back to the AC to be chilled or heated.

Do not purposely close off the ductwork in rooms that are not being used. Otherwise, the indoor air pressure will become unbalanced and cause your AC to work too hard, leading to early wear-and-tear and consuming a huge amount of energy. 

Same reason why you should always be certain that neither the supply nor the return ductwork is blocked by furniture, heavy curtains, or other household implements. 

Air filters should be routinely washed or replaced.

What Does an HVAC Ductwork Do?

Ductwork is an opening, a gap, or an access point that allows air to pass through into a confined space. In terms of air conditioning and heating, HVAC ductwork is used for the forced transportation of air, thus essential in keeping the air pressure in your living space at the right level.

You are likely familiar with how the air conditioner functions. In a nutshell, warm air gets drawn in from the living space to the AC unit, AC lowers its temperature with the help of refrigerant, then the cold air gets blown back into the rooms. 

If what you have in your home is a central HVAC system, the supply and return of air from the air conditioner and back happen in the ductwork—the channels or passages that move the processed air from the AC to various rooms inside your home, and the stale warm air gets carried back to the cooling device to be chilled and dehumidified. The ductwork serves as the gateway for these exchanges.

Of course, it cannot be called a cooling “cycle” if the cool air moves through the ductwork and out into the ductwork only once. As the AC pumps chilled air into the space through the supply ductwork, the return ductwork will take in more warm air for the unit to cool until the thermostat level is reached and the temperature around the house is finally comfortable.

What are the Different Forms of Ductwork?

If you search for online content about ductwork, you are likely to find these familiar terms: 

Supply Ductwork

Supply ductwork is usually smaller than return ductwork as they are linked to the supply ducts where cool, processed air comes out. You can see supply ductwork having slats so the user can direct the airflow in whichever direction he desires.

Return Ductwork

Return ductwork does the direct opposite of supply ductwork and sucks in the existing air from the room so its temperature can be lowered. They are naturally bigger than supply ductwork, and since their function is to draw more air to be recycled, return ductwork does not have slats or dampers for adjusting.

Do not be confused with the two other terms your contractor uses grilles and registers.


Grilles or some spell it as “grills”, are the type of ductwork found in walls, ceilings, and even floors. They can function either for supply or return of air. They allow free-flowing of air so they do not normally have levers you can adjust them with.


Registers are different in a way that they always come with a louver or damper. Modern designs are equipped with a rolling guide or a lever on one of its sides for easy maneuvering. The common purpose of registers is to deliver processed or chilled air to the spaces.

Why is Ductwork Essential to Home Comfort?

Although ductwork is relatively simple and has no complicated wiring or elements, they remain indispensable to the everyday cooling process. It is helpful in at least three areas of comfortable home living:

Proper Airflow

Without the ductwork, even the most powerful and expensive brand of central air conditioning will not be able to perform at its full capacity. Why is that? 

As the thermostat signals the AC to do its work of lowering the temperature, the blower motor will help draw in the warm air from the space into the mechanisms of the cooling unit. But how about the warm air that sits in other parts of the house? The ductwork is their only chance to get transported and recycled and come out as cool.

In the absence of warm air pulled through the return ductwork, the AC will interpret it as having finished its job and shut off prematurely. If the supply ductwork is also not being put to good use, this will result in one very cold and dry room and other rooms hot and humid.

Additionally, since homes with central air are strategically sealed off from leaks and holes, there would be no adequate airflow moving about inside your home. Without the ductwork, you will soon feel suffocated having to breathe in the exact recycled air as it had drawn.

On the contrary, if the ductwork is suitably installed and used, the air exchanges around your home would be efficient, regardless of which room you are in.

Better Indoor Air Quality

The state of indoor air quality depends on how healthy the breathing air is inside a home or office building, impacted by the presence of air pollutants found indoors.

Ductworks are extremely helpful in preserving good indoor air quality when they filter unwanted particles as it draws the air in through the return ductwork. These annoying particles include dust, dirt, pollen, animal hair or dander, small insects, and other solid fragments floating in your space.

Excess moisture also gets sucked in through the ductwork, leaving molds and mildew scarce places to breed and prosper.

However, if ductwork is closed off on purpose or accidentally gets blocked by furniture or heavy curtains, or other items, its capacity to filter the air gets compromised. This may also lead to certain areas of the rooms that are hard to reach gaining increased humidity, making way for dangerous molds and mildew.

As they grow rampant, allergies and other respiratory problems may be triggered in the family.

Lower Energy Consumption

It is no secret that AC consumes a significant amount of energy compared to other household appliances and devices. To combat this, some have been caught up in the idea that to save energy, the ductwork in rooms that are empty or not being used should be closed.

This could not be further away from the truth. If the AC started to blow the cold air it just processed, it would naturally find supply ductwork to release it through. The fewer ductwork that is opened, the higher the likelihood that it will escape through the ductwork leaks and cracks.

With the greater air pressure caused by having too few ductworks to release cold air, the number of leaks and holes in the ducts could even increase, wasting precious energy, leaving you with still high electric bills to pay, potentially expensive repairs and services, and uncomfortable living space.

Additionally, without sufficient warm air from the return ductwork, the evaporator coils are in danger of freezing up and your compressor is put at risk. Again, no comfort, yet costly utility and repair bills.

How to Properly Maintain and Care for Your AC Ductwork

The key to using the ductwork to your advantage is to let ductwork do its job: intake and distribution of air. Take notice of what may obstruct the ductwork from supplying cool air to the rooms or returning the warm stale and transporting it to the air conditioning system.

Here are some basic tips to correctly maintain your ductwork at home:

1. Do not fall into the wrong thinking of closing off the ductwork to save some bucks—it will do more harm than good.

2. When making modifications in your room by moving furniture around, be careful not to put anything in front of the ductwork that can hinder it from taking in or blowing air, such as furniture, heavy curtains, or any other household items.

3. Ductwork should be dusted and cleaned off. Be watchful against oxidation in metal grilles and vent covers. Consider hiring the services of a professional to check, clean, and maintain your ductwork.

 4. Filters inside the ductwork should be cleaned, washed, or replaced at least every one to three months, depending on whether there is already a buildup visible on it.

5. Make sure your ductwork is appropriately sized for your home and your HVAC system. Poorly sized ductwork and its unprofessional installation often lead to unmet cooling and heating needs, pricey yet unnecessary repairs and HVAC services, and unhealthy indoor air quality.

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