A cooling device called a ventless air conditioner sounds like an impossibility because air conditioners produce cold and hot air, so the hot air must vent out of the building.
Yet here we are with this exact cooling product advertised all over the place. It is generally a portable or free standing unit that you will see on display in many hardware stores.
So what exactly is it?
The reality is that a ventless portable air conditioner is a real cooling device, it's just not a traditional air conditioner as you know it!
Why an Air Conditioner Needs to be Vented
All refrigerant-based air conditioning appliances go through a process to produce the cold air that we all enjoy on a hot summer day. I'll describe the process as simply as I can so you won't need a degree in thermal engineering to understand it!
Warm air is taken from the room's atmosphere into the interior unit where it is passed through a kind of grid of very cold, narrow pipes, in much the same way a domestic refrigerator works to keep its interior cold.
These pipes contain a refrigerant gas that gets cold when it is compressed. The gas is compressed by a machine called, unsurprisingly, a compressor and is fed through the pipes by an internal pump.
The pipes form a circuit that leads the gas through the pipes where it loses its coldness as it expands, right back to the compressor to be compressed and continue on its journey through the circuit.
The compressor works hard to compress the gas and in the process, it gets very hot, creating a lot of hot air around it. That hot air is pumped out of the unit by a fan through vent pipes that lead to the outside, where the hot exhaust air is ejected to disperse into the atmosphere.
As I mentioned, that was a fairly simple explanation or the process, but it highlights how an air conditioner produces hot air as well as cold air.
Without the ability to vent off that hot air, it would instead be dispersed into the room being cooled, creating a net temperature increase and making the AC work very hard.
Hence the need for a way to release the hot air outside of the building. All air conditioning equipment has this feature, from central HVAC systems to fixed, zoned AC units, to window units and even portable air conditioners, the latter using a flexible hose attached to a window to exhaust the hot air.
When an Air Conditioner is Not an Air Conditioner
When you read about an air conditioner that is ventless, it is not actually an air conditioner at all.
It is a cooling device known as an evaporative cooler, also known as a swamp cooler.
An evaporative cooler creates cold air by evaporating moisture in a very simple process that starts with a tank of water, an absorbent media which is dipped in the water so it soaks it up and becomes wet and a fan that blow air through the wet media, evaporating the moisture which traps heat and blows out cold, moist air.
That process requires no heat-producing machinery like a compressor. So it doesn't produce any hot air. Just cold air.
Hence, an evaporative (swamp) cooler does not require a means of venting anything to the outside!
That makes it, in essence, a ventless air cooler.
There is a distinction here. It is an air cooler, not an air conditioner!
However, most swamp cooler models are portable and they do look, on the outside, a lot like portable air conditioners. Hence their being misnamed as ventless air conditioners!
So now you know!
Evaporative coolers are great for keeping you cool on a hot summer day, as long as your climate is relatively low in humidity.
If you live in an area with high humidity during the hot season, an evaporative cooler will not work so well and it would be a better choice to have a traditional air conditioner to keep you cool. But that's the topic for another article.
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