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Portable Air Conditioners - Single Duct VS Dual Duct

Portable Room Air Conditioning Units

Portable A/C Units Install Easily

Portable air conditioners are easy to install and maintain. There’s no heavy lifting required to position one precariously in a window as with window a/c unit. The most you have to do to install one once it is in your home is to simply plug it in and position the exhaust hose and (if applicable) intake hose in a window. Usually these are fitted to an adjustable plate and fitted into a window just like a window a/c unit, except they’re MUCH lighter.

A benefit of portable a/c units is that…they’re portable! Most models have castors or wheels installed on their base so that they can be moved from one room to another, without requiring any heavy lifting and awkward installation into a window.

Single Duct Portable A/C Units

The majority of portable air conditioning units use only a single hose that is fitted into the window. These are generally the cheapest units and offer a cooling capacity ranging from 6,000 to 12,000 BTUs. This makes them comparable, in terms of cooling ability, to cheaper window a/c units. The single hose is used to exhaust hot air from the condensing coils and humidity collected from the air in the surrounding room.

Dual Duct Portable A/C Units

Dual duct units offer a higher cooling capacity, usually maxing out around 14,000 BTUS. Obviously, the main difference is that they have one extra hose that is mounted in the window. One is an exhaust hose, like with a single duct unit, while the second hose is for an intake. This hose draws outdoor air through the unit to cool the condenser coils inside the unit and then exhaust the heat through the other hose. These models tend to cost more, yet they are the better option of the two types.

Rear Of Single Duct Portable A/C Unit

Which Is More Efficient- A Single Duct Or Dual Duct Portable A/C

With a single duct portable a/c, room air is used to cool the condenser coils in the unit and is then exhausted through the exhaust hose in the window. However, it doesn’t take a rocket scientist to realize that the air that is exhausted through the window must be replaced somehow. Usually, this will be air from nearby rooms or air from outside the home.

This lowers the efficiency of a single duct portable a/c unit because it must now also cool the air that has displaced the air being vented through the window. This means that a cheaper window a/c unit can be more efficient than a single duct portable a/c. This also means that it will take the portable unit longer to cool a room to a desired temperature.

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With a dual duct portable a/c unit, no indoor air is used to cool the condenser coils. They use outdoor air to cool the condenser coils and exhaust the heat outside. This means that it is more efficient, as cooled indoor air is not being wasted and exhausted outside. Therefore, dual duct portable a/c units can cool rooms faster and more efficiently than a single duct unit.

Which One Is Best?

It all depends on what you want to do. If you want to cool a room and not spend a lot of money up front and aren’t looking for a window a/c unit, then a single duct portable a/c unit will suit your needs. However, if you want to save money in the long run and cool your room or home as efficiently as possible, go with a dual duct unit. The cost of a dual duct unit is usually higher, yet it will pay for the increased price difference in the long run by reducing the amount of electricity used to operate it by reducing cooling times and increasing efficiency.


Jeremiah Simpkins (author) from Pulaski, VA on April 28, 2012:

With a dual duct a/c, the hot air from outside is not being vented into the room, it is being used to cool the condenser coils and is then vented back outside (now at a higher temperature than when it was drawn in obviously). The indoor air is cooled by passing it through the cooling coils and vented back into the room. The hotter outdoor air is not mixing with air in the room. It works just like a window a/c in principal, cooling indoor air with the cooling coils and using outside air to cool the condenser coils. I hope this clears things up.

Chuck Harris on April 28, 2012:

We live in the Arizona desert and the outdoor air many times reaches 125 degrees. What is the use of drawing in this hot air into an already hot interior? I would suppose that drawing hot indoor air into the system and cooling that would be more efficient instead of drawing hotter air into the system.

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