As most UK homes aren’t fitted with built-in air conditioning, a simple way to keep cool during the summer is by investing in a portable air conditioner.
Portable air conditioners are versatile appliances that can be placed (almost) anywhere in your home, provided there’s a window or door nearby. So if you’re considering making the splurge but aren’t sure how they work, we’ve got you covered.
We explain everything you need to know about how portable air conditioners work, how to use them effectively and what maintenance they need.
Otherwise, visit our best fan list for a more compact cooling solution, while our fans vs air conditioning guide will help you decide between the two.
How do portable air conditioners work?
Although a portable AC unit blows out cold air, they actually work by removing heat from inside and expelling it outside. To do this, there are two sides to an air conditioner: the cold side, and the hot side.
Inside, there’s a continuous loop that moves heat from inside to outside, using a refrigerant that changes state between a liquid and a gas.
The liquid refrigerant is pumped through a metal evaporator coil. A fan blows air from your room across the cold evaporator coil, where the refrigerant absorbs heat from the air, with cold air coming out of your AC’s vents.
This process causes the refrigerant to turn from a liquid into a gas. At this point, moisture from the air is removed when water condenses on the evaporator, as cold air holds less moisture than hot air.
This moisture is drained off and is usually evaporated and pumped out of the room, reducing relative humidity; in this way, air conditioners also work as dehumidifiers.
Next, the gas is pumped around the system into a compressor, which compresses the gas, increasing its pressure, temperature and its energy efficiency. This is now the hot side of the air conditioning unit.
The gas passes through a condenser coil, which has another fan that blows air over it. Here, the air absorbs the heat from the gas, and is pumped out through the duct hose out of a window or door and into the outdoors.
This causes the refrigerant becomes a liquid. Then, the refrigerant passes through the expansion valve, which relieves pressure, reducing its temperature. The cycle then begins again.
Do portable air conditioners use a lot of energy?
Generally speaking, how much energy used will depend entirely on the specs and energy rating of the portable air conditioner. For example, the De’Longhi Pinguino 100 Silent has an A++ rating and we measured it used around 640W of energy while running at its maximum setting, which roughly equated to around 15.6p an hour. This unit also cleverly shuts down once it reaches the set temperature, which means it won’t run unnecessarily and spike up the costs.
Meanwhile, we found the A-rated MeacoCool MC Series Pro 9000 BTU Portable Air Conditioner drew around 950W of power for similar levels as the Pinguino 100 Silent and cost 35.28p an hour too.
In the case of the Pinguino 100 Silent, the energy use is around 10 times that of a fan, but it’s important to note that fans don’t cool rooms down, whereas air conditioning does. If you need to remove heat from a room to make the environment more bearable, a portable AC unit is better than a fan.
What are the disadvantages of a portable air conditioner?
While portable air conditioners are a useful way to keep your home cool without needing to permanently install any equipment, there are some factors to keep in mind. One of the main potential disadvantages is that portable air conditioners need to be ventilated through a window, which can restrict where the unit can be placed.
Portable air conditioners also require some level of maintenance which can be seen as a nuisance by some. Finally, portable air conditioners can also be noisy which means they may not be deemed suitable for certain areas.
Do portable air conditioners need to be vented out a window?
Yes, portable air conditioning units should be vented out a window or through a door. This is because the vent takes the heat extracted from your room and vents it outside. If you don’t point the vent outside, then the hot air you’ve removed is just pumped back into the room, so you won’t see a cooling effect.
Can I use a portable air conditioner in a room without a hose?
No, as above, if you don’t attach the hose, then the hot air extracted from your room is vented back into your room, so you won’t see a cooling effect. If you fail to vent your appliance then you risk the air conditioner not working efficiently and potentially breaking down altogether.
Do portable air conditioners need to be drained?
Part of the AC process is that water is removed from the air when it hits the cold evaporator coil. In most cases, the moisture removed is evaporated and expelled with the hot air, rather than being stored in a hot tank, as with a standard dehumidifier.
However, in high humidity environments the process can be less efficient, and water can build up. Some portable AC units, such as the EcoFlow WAVE 2, have an optional drainage hose that can be attached to get rid of excess water.
All AC units will have a small water tank, with a drainage port at the bottom. For the most part, a portable AC unit should only need to be drained at the end of the season. Open the port and let the water out before storing the AC over the winter.
It’s worth checking your device’s manual as it will not only tell you where to find the port, but also explain the best way to drain the water, and how often should do this.
Most portable air conditioners will indicate when to drain the appliance, but the exact timings will depend on how often you use the device and how much moisture it collects. Again, check your device’s manual for the specifics.
