Do Ventless Portable Air Conditioners Really Work?


Some people just want a small cooling and they are thinking about getting a ventless portable air conditioner. So, does a ventless portable air conditioner really works?

Ventless portable air conditioners are not effective when using in humid places due to the nature of evaporative cooling. The higher the relative humidity, the lower the cooling effect of the ventless portable air conditioners. Conversely, ventless portable air conditioners are very effective when using in humid places such as Chile, Mexico, Saudi Arabia and west United States.

Many people misunderstand that ventless portable air conditioners work just like air conditioners because they have the word “air conditioner”. However, they are not the same at all. In my opinion, ventless portable air conditioners should be called evaporative coolers or air coolers so that they are separated and not categorized as air conditioners.

How Ventless Portable Air Conditioners Work?

Ventless portable air conditioners are not the same as air conditioners. Ventless portable air conditioners absorb heat using the evaporation of water to provide cooling. Contrarily, air conditioners transfer heat from indoor to outdoor using refrigerants to provide cooling. Ventless portable air conditioners not only unable to reduce the humidity of the air like air conditioners do, but they increase the humidity of the air.

On average, ventless portable air conditioners produce air at about 80% relative humidity. If a room has a relative humidity of 40%, ventless portable air conditioners provide remarkable cooling to the room. However, as the room approaching 80% relative humidity, the cooling effect gradually reduces and finally disappears.

Ventless portable air conditioners provide cooling using a process called evaporative cooling where liquid water absorbs the heat and vaporizes. Therefore, a hose is not needed to vent any heat to the outside of a house. But, ventless portable air conditioners consume water. Thus, you'll need to constantly refill the water.

Image source: Orient Electric

You can view evaporative cooling as sweating in humans. Notice that when you sweat, you feel cooler especially when there is a wind blow because the sweat water absorbs the heat from your body and vaporized, carrying away the heat and cools your body. Similarly, a ventless portable air conditioner absorbs the heat in your room to “boil” and evaporate the water. Thus, provides cooling to your room.

On the other hand, air conditioners have compressors, cooling coils and expansion valves which are the core components for the refrigeration cycle. Air conditioners absorb heat in your room and reject the heat outside your house. Air conditioners provide both cooling and dehumidification.

Ventless vs Vented Portable Air Conditioners

While ventless portable air conditioners use evaporative cooling, vented portable air conditioners are true air conditioners that use the refrigeration cycle to provide cooling. Some of the differences between ventless and vented portable air conditioners are as follow:

  • Cooling power – Ventless portable air conditioners are unable to provide cooling as much as vented portable air conditioners.
  • Dehumidification – Typical ventless portable air conditioners are not able to remove any moisture in the air while vented portable air conditioners are capable of dehumidifying air to a comfortable level.
  • Comfort – Vented portable air conditioners usually provide much better comfort than ventless portable air conditioners because they also remove moisture in the air.
  • Weight – Ventless portable air conditioners are much lighter than vented portable air conditioners because they don't have components such as the compressor.
  • Cost – Ventless portable air conditioners are cheaper than vented portable air conditioners.

In addition, a ventless portable air conditioner will never show any cooling capacity (BTU) like a vented portable air conditioner does. It often only states the airflow rate and water storage volume.

In summary, you should not expect a ventless portable air conditioner delivers cold air the same as an air conditioner. The cold air from a ventless portable air conditioner does not feel the same as an air conditioner because it is more humid.

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Are Ventless Portable Air Conditioners Any Good?

However, ventless portable air conditioners can perform very well in certain applications. As discussed earlier, ventless portable air conditioners use evaporative cooling and it is heavily dependent on the relative humidity of air in your area. If you are living in places where the relative humidity is high, a ventless portable air conditioner doesn't cool much or not cooling at all.

Ventless portable air conditioners are best-suited for low humidity and high temperature countries such as:

  • Egypt
  • Saudi Arabia
  • Pakistan
  • Australia
  • Chile
  • Mexico
  • United States
  • West China

Besides, ventless portable air conditioners may be used outdoor since the outdoor air won't increase the relative humidity like a room does. Hence, the ventless portable air conditioners can provide a consistent cooling effect.

Vented Portable Air Conditioners But Without Hose

If you have a vented portable air conditioner, you need to connect a hose to let the hot air discharging to the outside. Although vented portable air conditioners can still operate without the hose, you can't get any cooling because the heat absorbed by the air conditioner is not going anywhere but circulated back in your house.

Vented portable air conditioners are meant to have a hose to discharge hot air to the outside. Without it, a vented portable air conditioner not just unable to provide cooling, but it also wastes a significant amount of energy and thus, costs you nothing but money.

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