How Ventless Portable Air Conditioners Work, Pros & Cons

Air Conditioners work by absorbing heat from the indoor air and dumping it to the outside. That is why they have an indoor and an outside unit.

The inside unit absorbs heat from the air using a refrigerant, then the refrigerant releases the heat outdoors through the outside/condenser unit. However, if you want to cool only a small space, portable air conditioners is what you are likely to consider.

ventless portable air conditioner

While portable air conditioners do not have an outside unit, they have an exhaust hose to vent the hot air to the outside. As you can see, air conditioners will always need a way to release the indoor heat to the outside.

If that is the case, what then are ventless portable air conditioners and how do they work? How can an air conditioner work without being vented?

As a matter of fact ventless portable air conditioners are not air conditioners in the real sense. Their correct name is swamp coolers or evaporative coolers.

Have you ever sat/stand by a waterfall or river on a hot day? I am sure it felt cool just being there. Why is that though? That is how ventless portable air conditioners work.

A Ventless portable air conditioner is a system that cools air by evaporating water. It draws hot air and passes it through a moistened pad. The water in the pad absorbs heat from the air and cooler air (by up to 30 degrees) emerges from the other side of the unit.

Ventless portable air conditioner use the natural power of evaporation to remove heat from air. A unit with a water reservoir at the bottom and a moistened pad pulls warm air from the house and as the air passes through the wet pad, the moisture absorbs heat from the air, cooling it in the process.

How Ventless Portable Air Conditioners Work

When you stand close to a water body (like a waterfall or river), there is that cooling breeze which sweeps across you even on a very hot day. That is because the water body absorbs heat from the surrounding air and hence the cool breeze.

That is the same principle employed by ventless portable air conditioners. Another example is sweating. We feel cooler after sweating because as the sweat evaporates, it takes away heat with it thus creating a cooling sensation.

Water is an excellent coolant. That is why it is used in most factories to cool down machines.

It is very easy to understand how an evaporative/swamp cooler works. It is mainly made up of the following components:

  • Water reservoir – The water reservoir is located at the bottom of the unit hence it makes the unit very stable. It basically supplies the cooling pad with water for the cooling process and needs to be refilled when the level is low.
  • Cooling pad – The cooling pad is made from an absorbent material and is located near the front of the unit, installed vertically. It draws water from the reservoir for the cooling process.
  • Fan – Just like with normal air conditioners, the fan draws hot air from the room, forces it through the cooling pad and then circulates the cooled air back to the house.

Since the cooling pad is made from an absorbent material, it easily soaks up water from the reservoir. For evaporative coolers to work, the cooling pad must always be moistened.

When the unit kicks in, hot air is pulled from the surrounding and forced through the moistened cooling pad. The water in the pad absorbs heat from the air and the cooled air is then circulated back to the house with the help of the fan.

Since the evaporation process removes moisture from the pad, the pad will keep on soaking more water from the reservoir and that is why you need to monitor the water level in the reservoir and top it up if need be.

Ventilation is important when running a ventless portable air conditioner. You will therefore need to open a door or window to bring in fresh air otherwise the unit will keep circulating the same stale air.

Who Should Buy a Ventless Portable AC and Who Shouldn’t?

Ventless portable air conditioners are a great choice in hot and dry areas like the South West of the United States. The air there is hot but dry (does not have a lot of moisture in it).

The main reason other types of air conditioners are so popular is that apart from cooling the air, they also reduce the humidity in the house. Ventless portable air conditioners are not great dehumidifiers. In fact, they increase relative humidity in the house.

High humidity is usually not a concern in South Western states like Arizona. Ventless portable air conditioners are therefore a good choice in such areas.

If however you live in humid states like Florida, you should not consider a ventless portable air conditioner for your indoors. The relative humidity indoor will just be too high.

However, if you intend to use a ventless portable air conditioners outdoors, it will be a great choice wherever you live.

Vented vs Ventless Portable Air Conditioners

Needless to say, the main difference between vented and ventless portable air conditioners is venting. A vented air conditioner will need to be vented to the outside through the window to remove the heat absorbed the unit.

In instances where there is no window or venting the unit through the window is not possible, the units can be vented through the wall, door, dryer vent, ceiling or even chimney. Check out this post for more details on that.

Vented air conditioners work by pulling warm air from the room and passing it through an evaporator coil filled with a refrigerant. The refrigerant absorbs heat from the air and that is how cooling happens.

When the air is cooled, the moisture present in the air condenses and collects in a condensate tank at the bottom of the unit. That is how these units lower the indoor relative humidity.

After absorbing heat from the air, the refrigerant evaporates and it flows to the compressor where it is compressed before entering the condenser coil.

Inside the condenser coil, the refrigerant is forced to release the heat it absorbed from the air and that is where venting comes in. Without venting, the heat would be circulated back to the house.

An exhaust hose is thus used to exhaust the hot air to the outside. Some AC units have 2 hoses, one for exhausting the hot air and the other one for bringing in fresh air.

Advantages of Ventless Portable Air Conditioners

The following are the advantages of ventless portable air conditioners:

1. High Efficiency

Ventless portable air conditioner are way more efficient than vented portable air conditioner. As a matter of fact, they use 10 times less energy than vented air conditioners. They usually use between 100-150 watts per hour.

Unlike other air conditioners which use a complicated cooling system, ventless portable air conditioners use the natural evaporation cooling process which makes them very efficient.

2. No Installation Needed

Ventless portable air conditioners don’t need to be installed. You only need to plug them to a power outlet and that is it.

On the other hand, regular air conditioners need to be installed in order for them to work. Even portable air conditioner needs to be vented so that they can remove hot air to the outside.

3. They Look Neat

One thing I don’t like about vented portable air conditioners is their look. The vent is not very attractive and the fact that it has to go out through the window makes it quite conspicuous.

Ventless air conditioners don’t mess with your house’s aesthetics. They look neat and unlike vented portable ACs which are installed close to windows, you can place these units just about anywhere in your house.

4. Can Be Used Indoors and Outdoors

Ventless portable air conditioners can be used both indoors and outdoors. If you have an outdoor space that you would like to cool then you may very well consider one of these units.

While using regular air conditioners, we try as much as possible to seal the house to prevent outside air from from entering the house. That is because outside air would reduce their efficiency. Now try installing those units outdoors.

5. Easily Portable

Evaporative coolers can be moved from one room to another and from the indoors to the outdoors. They are more portable than vented portable air conditioners.

With vented portable air conditioners, you have to move the unit together with its exhaust hose and you can only move it to a room with a window. That is unless you want to use the unit in its dehumidification mode only.

6. They are Inexpensive

The upfront cost of ventless portable air conditioners is also way less compared to other types of air conditioners. If you are therefore looking for a budget-friendly option for cooling a room, you should consider an evaporative cooler.

7. Low Maintenance

It is cheap to maintain an evaporative cooler compared to other types of air conditioners like vented and window air conditioners. Normal air conditioners have way more components which need to be serviced regularly but you will hardly ever need to call an HVAC professional to fix your swamp cooler.

Disadvantaged of Ventless Portable Air Conditioners

Despite their benefits, ventless portable air conditioners have some limitations which may persuade you not to consider them.

The following are the disadvantages of ventless portable air conditioners:

1. Can’t Be Used in Humid Climates

The fact that ventless portable air conditioners add moisture to the air means that they are not a good options for people living in humid areas. High relative humidity can promote the growth of mold and can also make you sick.

Folks in humid areas can however buy these units if they intend on using them outdoors.

3. Not Very Powerful

You cannot compare the output of a window AC unit and that of ventless portable air conditioner. Also, you need to remember that humidity makes a room hotter than it actually is.

By reducing humidity (which regular ACs do), the air also feels cooler. That is also the reason why dehumidifiers don’t cool rooms but actually make it feel colder.

4. Takes Time to Cool

Vented air conditioners cool a room almost immediately. However, ventless portable air conditioners take time before they can sufficiently cool a room.

Wrap Up

And basically that is everything about ventless portable air conditioners. I hope that by now you know everything you wanted to know to make an informed choice.