Single Hose vs Dual Hose Portable Air Conditioners

There is some confusion over how efficiently a venting system is, so we take a look at single hose vs dual hose portable air conditioners to see which is the best option.

First, however, here is a short description of what the flexible, corrugated plastic vent hose is actually for.

What is the Hose For?

portable air conditioner dual hoseWhen people buy a portable air conditioning unit for the first time, they are sometimes a little perplexed at what the flexible hose accessory is used for.

Although it may seem a little like something a stand up comedian would talk about, this often occurs for that special kind of person that never reads the instructions before plugging in and waiting for something to happen!

The hose is meant to carry hot, moist air away from the unit to the outside air through a window opening generally via a special fixing kit that is included with free standing air conditioners. That means it must be connected from the back of the AC unit to the window.

If the hose is not connected, the hot air will pump out the back of the unit into the room, leading to a net INCREASE in temperature.

This is because the refrigeration process in the AC unit produces more hot air than cold!

Note: Hot air venting does not apply to swamp coolers, which are often referred to as ventless portable air conditioners. These non-refrigerant-based evaporative cooling units do not produce any hot air to be vented.

Is a Single Hose Enough?

Most portable AC models come with a single hose configuration and that is sufficient to expel the hot air out of the room to the outdoors.

The unit will function perfectly well and keep you nice and cool indoors.

However, there are some advantages to making use of two hoses, as I will explain below:

Advantages of Duel Vent Hose Configuration

Double-hose portable air conditioners offer many advantages over single-hose units and is linked to the way dual-hose units function.

These include better efficiency as air is drawn in from outside and the elimination of negative pressure problems inside the room. Here's why:

Dual-hose AC units are balanced in air intake and output, whereas single hose units are not.

A single-hose unit may achieve an energy efficiency rating of 10 EER, but a regular or self-evaporating portable air conditioner with dual vent hoses can achieve an 11+ EER rating and consumes less electricity, making it more energy efficient.

The unit can be heated less and has a greater capacity. Portable AC units that have two hoses can provide more airflow than single-hose units. They also don't require as much mechanical work to produce 10,000+ BTU cooling power.

Better Filtering

Double filtering improves the filtration system, improving indoor air quality.

A simple switch from one-hose to another makes a huge difference. Double vent units have a balanced flow of airflow, as the air intake from outside is the same as the air exhaust to the outside.

The volumetric exchange reduces indoor pressure fluctuations. The indoor pressure remains the same, and doesn't fall like it does with single-hose units that draw air in from inside

Pressure Balance

Dual-hose units require less energy to produce the same cooling effect. They don’t have to pump air against a negative pressure difference. This gives rise to:

The cost of dual-hose portable air conditioners is 10-20% higher than the same-BTU single hose units. However, that's just for the unit price.

Because of their higher energy efficiency, electricity savings can make up the difference within a few year. Twin hose AC units are less expensive than single hose ones in the long-term.


There are 4 specification criteria to consider when choosing a dual-hole portable air conditioner

These metrics should be checked before you purchase a dual hose air conditioner.


Portable AC units with two hoses follow the same selection criteria as any other unit, whether it is central AC, ductless mini-split AC, PTAC/VTAC, portable AC or window air conditioner.

With dual hose free standing air conditioners you get better efficiency, energy efficiency and output over single hose models.

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