Ducted vs Ductless Air Conditioning Systems

Air conditioning is often one of the prime considerations when dealing with commercial or residential buildings. Whether you are renovating your house, or drawing up plans for your new dream home, you will inevitably be faced with the choice between a ductless system and a ducted one. This can quickly become a daunting task.

Both ducted and ductless heating or cooling systems come in multiple types under several brands. Let me take you through the basics of both systems and their advantages plus disadvantages. I hope that this article would help you in making a qualified decision for your next heating or cooling system purchase.

Ducted Air Conditioning Systems

As the name suggests, ducted air conditioning provides heating or cooling through a system of ducts spread out all over your home or commercial space. A central unit, consisting of a condenser, compressor, and an air handling unit, is usually located in the basement, attic, or garage. It provides cool or hot air, which is then distributed throughout the building through a series of ducts and vents, providing the appropriate climate control.

Types of Ducted Air Conditioning Systems

Ducted systems are also called central air conditioning systems. They can be broadly segregated into two types, i.e., Split type central air conditioners and packaged central air conditioners.

Split Central Air Conditioners

These systems are by far the most common type of central air conditioning system currently being used. They consist of the condenser and compressor placed outside in one package. A separate evaporator is placed indoors within a segregated container, usually located in a closet or the attic. The outdoor unit provides the refrigerant to the evaporator, which then cools the air and pumps it down the network of ducts through an air handling unit.

As is evident from the name that these systems split the unit into two parts, with the condenser and compressor placed separately from the evaporator. If a property already has ductwork installed for a furnace, then split type central air conditioners are the most convenient choice.

The reason why these systems are placed separately is mainly due to their size. Split central air conditioners are usually three times the size of an equivalent packaged central air conditioner. Split systems have much higher efficiencies (SEER) as compared to packaged air conditioners.

Packaged Central Air Conditioners

In such a system, all the components, including the condenser, compressor, and evaporator are situated in one singular unit. It can be placed either outside beside the wall of the building, or on the roof. This type of system is best suited for commercial buildings, or already built homes, where space can often be limited indoors. Large ducts then circulate the air form the air handling unit into the room, and also to circulate it back to the unit. These systems can be coupled with heating coils or furnaces to also provide heating facilities.

Packaged central air conditioning systems provide generally lower efficiencies than split systems but have the added advantage of not taking up any space inside the home.

Before going for packaged central systems, be careful to check out your outside space well in advance. These systems can be heavy, so the roof should be able to adequately handle the load. Or if you’re placing it on the ground, concrete emplacements need to be dug in before commencing further.

Another important consideration while choosing ducted air conditioners is the ductwork. After all, it is what the system is named after!

Types of Ducts for Ducted Heating or Cooling

Ducting makes up a major component of central air conditioning systems. These are channels for the air to travel throughout the home. There are two duct systems currently being used:

1. Flexible Ducting

These AC ducts are large diameter, tube like structures, made up of a mixture of metal framework surrounded by flexible plastic and insulation. This type of ducting is often cheaper and easier to install. It is best suited to confined spaces, where rigid structures can often be hard to install, or at the ends of a rigid ducting network, to connect it to the air outlet. An important consideration while installation of flexible ducting is to ensure that there are no kinks or bends, which might hamper airflow.

2. Rigid Ducting

As the name suggests, these AC ducts are fixed structures used to distribute air across an internal space. They are sturdier and more durable than flexible ducts, but at the same time, harder to install. They are usually made of metal. The use of fiberglass instead of metal serves to reduce noise levels coming from the air conditioning units. But it has the disadvantage of being a potential health hazard, where deteriorating and old fiberglass lining can release fiberglass particles into the air.

Now that we’ve had a general overview of central or ducted air conditioning systems, let us go over the pros and cons of them:

Pros of Ducted Air Conditioning

• According to the EIA, 91% of homes built in the US since 2000 have central ducts included. So chances are, you’ve already got a duct network within your property. If that’s the case, opting for a ducted air conditioner is a no brainer. This will also radically decrease the installation costs.
• The vents used in ducted air conditioning systems give out an unobtrusive and discrete outlook. So if you are one for aesthetics, these systems are for you.
• Ducted air conditioning remove humidity at a much greater rate than their ductless counterparts. While living in a humid environment, where moisture control is a priority, these systems come out on top.
• If your target space is a large room with many people inside, such as a restaurant or workspace, then ducted systems provide enhanced airflow than ductless systems. A greater rate of air flow ensures it never gets too stuffy, and you are constantly provided with fresh air circulation.

Cons of Ducted Air Conditioning

• Ducted air conditioning usually have higher installation costs, especially if installation is being performed in an already installed property where duct space has to be made.
• Ducted air conditioners, on the average, present lower efficiency ratings, called Season Energy Efficiency Ratios (SEER), for the same cost as their ductless peers. Leaks or damages to the ducts can further reduce the efficiency of the system, resulting in even higher operating costs.
• These systems are generally maintenance intensive, with ducts requiring regular upkeep and monitoring. According to the EPA, upto 30% of the air is lost through leaks, holes, and improperly installed joints within the AC ducts.
• Mold in AC ducts can accumulate over time, and also serve as a breeding ground for insects. Such contaminants, when introduced to the room along with air, can result in allergies and diseases.

Ductless Air Conditioning Systems

As is obvious, these systems do not employ any type of ductwork to move air from one space to another. Instead, these are standalone systems, where the conditioned air is introduced into the room through an air handling unit installed within the room. This indoor unit is supplied with the necessary refrigerant through an outdoor unit, or is installed within the same package as the indoor unit.

Types of Ductless Air Conditioning Systems

There are various types of ductless air conditioning systems and heat pumps in the market. Let’s go over the major ones:

Wall Mounted Mini Splits

Ductless mini split air conditioners consist of the indoor unit being mounted high up on the wall, while the outdoor unit is placed outside, either on the ground or on a stand attached to the wall. Both the units are connected with each other through a small pipe bundle, consisting of piping for the refrigerant, condensed water, and also a power cable. This bundle is passed through a small unobtrusive hole in the wall. These air conditioners provide the flexibility of zone control, allowing the user to set the climate of each room individually. Latest technology allows the same mini split units to work as reversible heat pumps as well, supplying heat in the winter months.

Wall Mounted Multi Splits

These systems are very similar to wall mounted ductless mini split air conditioners, with the notable difference being that instead of one outdoor unit powering one indoor unit, the outdoor unit can be used to power up multiple indoor units. The basic principle is the same, but a larger outdoor unit is required to supply the necessary power to the multiple systems.

Window Units

Instead of having a separate indoor and outdoor unit, both the evaporator and condenser are packaged into one housing, and installed on a window. The interior air is cooled by the evaporator, while the absorbed heat is blown outside. Within a large home, multiple units may be installed, with one in each room to provide adequate cooling.

Portable Air Conditioners

With all the components being housed in one package, portable air conditioners are very similar to window air conditioners, but the notable difference is that the portable ductless air conditioner can be put up anywhere, as required. The unit is usually on wheels, or sufficiently lightweight so it can be transported around easily. These units have a hose which can be extended and placed outside, to provide for an outlet for the heated air venting from the condenser.

Cassette type Air Conditioners

Cassette air conditioners are usually found recessed within ceilings of the room. Much like a wall mounted split unit, they have an outdoor unit which is used to transport the refrigerant to the indoor air handling blower. They are usually found in larger sized rooms, such as shopping stores or workspaces.

Now that we’ve had a general overview of ductless air conditioning systems, let us go over the pros and cons of them:

Pros of Ductless Air Conditioning

• Ductless AC systems leave a much reduced footprint in the house than ducted ones. This is due to the absence of any ducting or a large condenser/air handling unit. This makes them ideal when renovating a space, where there is minimal room for ducts.
• Multi zoning can be achieved through the use of mini splits. Each rooms’ temperature can be individually altered as per need, without having to change the whole homes’ temperature. Even though it is provided with ducted systems, but they are usually expensive.
• Ductless AC systems provide enhanced efficiencies compared to their ducted counterparts. SEER ratings can be as high as 30 for some systems.
• An increasing number of electric utility companies are now providing rebates and financial incentives to home owners to install mini splits, due to their higher efficiencies.
• Inverter technology incorporated inside ductless systems enables the compressor to speed up or slow down as per demand, resulting in decreased energy usage.
• Better air quality is obtained through the use of ductless systems. Absence of ducts removes any potential for dust and contaminants. Filters can be easily removed and cleaned, with newer models having air purifying technology built in.

Cons of Ductless Air Conditioning

• Ductless AC systems require a unit to be placed within the room. These can often be obtrusive and an eyesore.
• Ductless AC systems have a higher initial installation cost than ducted systems. This can be recovered over their lifetime, but it depends on specific geographical conditions and AC usage.
• Ductless AC systems, generally, do not provide the large levels of air flow which are observed with ducted systems. If you’re looking to put in large volumes of air in a large space, then ducted systems are the better option.

Which One to go for?

There is no hard and fast rule about when to go for ducted air conditioner or ductless. HVAC systems are a complex piece of engineering, with many considerations which need to be taken into account. The final choice boils down to the specific needs of the user. Whether they are installing the system in an already built property, or one they are building from scratch? What is the area of the space they are heating/cooling? What is their budget? Whether they want individual zonal control or not? All these questions, and many more, need to be answered before going out and buying a suitable air conditioning system. Happy hunting!

Originally published at https://www.cielowigle.com on November 27, 2019.