Portable ACs work by removing the air from a room, cooling it, expelling it back into the room and exhausting the leftover heat through a tube typically connected to a window. There are three main types of portable ACs on the market. While some might be more expensive, depending on the size of the area you are trying to cool and the environment you are in, one could be more beneficial than another.
✔️ Single-hose: The most typical portable AC, a single-hose model draws in air from the room, cools it and expels extra heat through a hose. By connecting the hose to the window outside, you only get the cool air within the room. At the same time, because there is only one hose, the AC draws in more air from the room to cool down the internal components that have gotten hotter due to constant cooling. This creates a negative pressure within the room, which essentially means that air will try to come in through any openings (door, cracks, window, etc.) at a higher rate than normal. This, in turn, makes the AC work harder to cool that extra air. Therefore, it is so important to properly seal the window after installing the portable AC. These are typically cheaper than dual-hose units.
✔️ Dual-hose: Dual-hose ACs work slightly differently than single-hose units and are more efficient. Dual-hose portable ACs utilize both an intake hose and an exhaust hose, both of which connect to the same window. The exhaust hose doesn’t do anything differently; it is still used to expel extra heat. The intake hose has two main uses: It prevents negative pressure and cools down the internal components of the machine. Bringing in external air to cool the system instead of air from within the room bypasses the negative pressure issue, which is why dual-hose units can cool bigger rooms and tend to have a higher energy efficiency rating. This is also why dual-hose units tend to be more expensive than other portable ACs.
✔️ Evaporative cooler (EC): This is a very different type of portable AC and only technically makes this list because 1. It is portable and 2. It’s meant to cool an area — but it is not the same design as either of the above. ECs do not have exhaust tubes or intake tubes. They use the process of evaporative cooling to cool a space. The only internal moving part of the EC is the fan inside. An EC typically contains a water reservoir and cooling pads. When the fan draws in hot air across the cooling pads that have absorbed water from the reservoir, the water slowly evaporates. That process of evaporation creates cooler air which is then expelled back into the room. ECs use much less energy than any other AC type, as they do not have internal parts that do the cooling. As it doesn’t need any form of proper exhaust, you can use this in any space and even outside.