COSTWAY 5 in 1 Portable Air Conditioner Review: a chunky but handy all‑year unit if you accept the noise

I’ve been using this COSTWAY 5 in 1 portable air conditioner (the 12,000 BTU version) for a few weeks in a small flat, and I’ll be honest: I bought it mainly because I can’t install a split unit and I was sick of roasting in summer. I also liked the idea that it could heat in winter and act as a dehumidifier. On paper, it covers a lot: cooling, heating, fan, dehumidifier, timer, sleep mode, remote, window kit – basically the usual portable AC Swiss army knife.

In practice, it’s exactly what it looks like: a big white box on wheels that moves a lot of air, makes a fair bit of noise, and keeps a medium-sized room at a decent temperature if you set it up properly. It’s not magic, it’s not silent, and it’s not tiny. But if you’re in a rental or can’t drill holes in walls, it’s one of those “good enough” solutions that gets the job done as long as your expectations are realistic.

I used it mainly in a bedroom of about 15–18 m² and occasionally in a living room around 22–24 m². The advertised 18–25 m² cooling capacity is roughly accurate, but you need to keep doors and windows closed and accept that the unit will run for a while before the room feels properly cool. If you’re expecting instant hotel-style cold air in a huge open-plan space, you’ll be disappointed. For a standard bedroom or home office, it’s fine.

Overall, my feeling is: solid performance for the price, but you have to live with two big downsides – the noise and the bulk. If you’re sensitive to sound when you sleep, you’ll want to read carefully, because the 65 dB rating is not a joke. If you can tolerate some background hum and want a flexible all-in-one machine you can roll between rooms, it’s worth considering.

On value, I’d put this COSTWAY unit in the “good but not unbeatable” category. You’re paying for a decent 12,000 BTU machine that can cool, heat, dehumidify and act as a fan, with a remote and full window kit included. Considering some brands charge similar money just for cooling without heating or dehumidifying, it’s not a bad deal. The 4.4/5 rating on Amazon (from a few dozen reviews) lines up with my experience: most people seem satisfied, with the main complaints being noise and the fact that it’s not some miracle climate control machine.

Compared to cheaper portable ACs around the 9,000–10,000 BTU mark, you do feel the extra capacity. Cooling is quicker and it handles slightly larger rooms better. If you live in a place that gets properly hot in summer, I’d rather spend a bit more on 12,000 BTU than save a small amount and end up with an underpowered unit. The heating function isn’t a full replacement for proper heating, but it does add some value if you use it mid-season or in a spare room.

Where the value is less convincing is if you’re very sensitive to noise or if you have the option to install a split system. A fixed split unit will cool better, be much quieter, and often more efficient in the long run – but of course, it’s more expensive upfront and requires installation. If you’re renting or can’t drill walls, then portable is your only realistic option, and in that context, this COSTWAY makes sense. You just have to accept the usual portable AC compromises: window kit, hose, noise, and a big box in the room.

So, is it good value? For someone in a flat or rented house who needs a flexible, movable unit for one or two rooms, yes, I’d say it’s good value for money. It’s not the cheapest, but you get solid cooling, a few extra modes, and a relatively complete package. If you’re on a tight budget, there are simpler, noisier units that are cheaper. If you want something quieter and more efficient, you’ll need to spend more or go for a fixed installation. This one sits comfortably in the middle.

Design-wise, don’t expect anything fancy. It’s a big white rectangular box: 38 cm deep, 44 cm wide, and 79 cm high, weighing about 31 kg. So yeah, it’s not light, and it’s not something you casually pick up and carry up stairs. The good news is that it has proper caster wheels and recessed side handles. On flat floors, it rolls easily from room to room. I moved it between bedroom and living room without too much effort, but lifting it alone is not fun.

The control panel is on top, which is practical. You stand over it, press the mode, adjust temperature, fan speed, timer, and that’s it. The LED display is bright enough to read in daylight and not so bright that it blinds you at night, which I appreciated in the bedroom. The remote mirrors the main buttons and works fine from across the room, as long as you’re roughly pointing in the right direction. No app control in practice, despite the spec sheet mentioning app control – mine is just remote and touch panel, and that’s honestly enough.

The window kit is the usual story for portable ACs: a telescopic plastic panel that you fit into a sliding or sash window and connect the exhaust hose to. It works, but it’s not perfect. You’ll probably need to fiddle with it a bit to get a good seal, especially if your window is not a standard size. I ended up adding some foam tape around the gaps to stop warm air from leaking back in. Once that’s done, it’s stable enough and does the job, but it’s not a super polished solution. If you’re renting, it’s still much better than drilling holes in the wall.

The exhaust hose is thick and a bit stiff, and it takes up space. You need to account for that when you place the unit: it can’t be right up against the wall, and you’ll lose some usable space near the window. The overall look is very “appliance” – nothing stylish, but neutral enough that you stop noticing it after a while. If you want something discreet and compact, this is not it. If you just want a functional box that moves air and you don’t care about aesthetics, you’ll be fine.

From a comfort point of view, this unit is a bit of a mixed bag. On the positive side, the airflow is strong and you feel the cool air quickly if you’re in the path of the vent. On the hottest days, sitting a few meters in front of it is honestly a relief. The adjustable louvers let you tilt the airflow up or down, so you can avoid having it blow straight in your face while you sleep. Once the room has cooled down, the overall climate feels much more bearable, and that’s really why you buy this thing.

But comfort isn’t just temperature – it’s also noise and how invasive the device feels. And here, the 65 dB rating really shows up. Even on low speed, there’s a constant hum plus the compressor kicking in and out. In the living room while watching TV, it’s okay if you turn the volume up a bit. In a bedroom at night, it’s more borderline. Personally, I could sleep with it on low or in sleep mode after getting used to it, but my partner hated the sound and preferred to cool the room before bed and then turn it off.

The sleep mode itself is fairly simple: it gradually adjusts the temperature by about 1°C after an hour, then again after another hour, and it tends to keep the fan on a lower speed. The idea is to avoid overcooling while you sleep. It works in that sense, but it doesn’t make the unit quiet. If you live on a noisy street anyway, the AC just adds to the general background noise. If your house is usually very quiet, you’ll notice it a lot more.

One comfort detail I did like is the 24-hour timer. I often set it to stop after 2–3 hours at night, which cools the room enough to fall asleep, and then it shuts off automatically, so you get some quiet later in the night. During the day, the noise bothered me far less, and the strong airflow was actually pleasant. So comfort is good temperature-wise, but only if you’re ready to compromise on sound levels and live with a big white box parked by your window.

In terms of build, the COSTWAY feels like a typical mid-range portable AC: solid enough plastic shell, nothing premium, but it doesn’t feel flimsy either. The casing doesn’t creak much when you move it around, and the wheels seem sturdy. I rolled it over tiles and laminate several times a day for a couple of weeks and nothing felt loose or wobbly. The exhaust hose locks into place properly and didn’t pop out or crack, which is something I’ve seen on cheaper units.

Maintenance is basic but important. The air filter is removable and easy to rinse under a tap, which is all you really need for this type of device. If you’re in a dusty environment or have pets, you’ll want to clean it regularly; otherwise, the airflow drops and the unit has to work harder. The user guide is clear enough about this, and the process is quick – you slide the filter out, rinse, dry, slide back in. Nothing complicated.

As for the R290 refrigerant, there’s a lot of noise online about it being flammable and so on, but in practice, the system is sealed, and this is standard for modern portable units in Europe. Unless you physically damage the unit, you’re not going to notice anything. One of the Amazon reviews even goes into detail explaining why it’s considered safe in this type of enclosed appliance. I didn’t see any leaks, weird smells, or anything concerning while using it.

Long-term durability is hard to judge after just a few weeks, but based on the feel and the 1-year warranty, I’d say it’s okay but not bulletproof. It’s not a high-end industrial machine, but it doesn’t feel like a toy either. If you treat it decently – don’t bash it into furniture, keep the filter clean, and store it properly off-season – I’d expect it to last several summers. There are better-built units on the market, but they usually cost more. For the price bracket this sits in, the durability and build quality seem reasonable.

On pure performance, I’d say this COSTWAY sits in the “pretty solid” category. The 12,000 BTU cooling is enough for a typical bedroom or office, and just about enough for a medium living room if you don’t have massive windows baking in the sun. In my 15–18 m² bedroom, I could drop the temperature from around 27–28°C to 22–23°C in under an hour with the door shut and curtains drawn. Once it reaches the target, it cycles on and off and holds the temp reasonably well. If you leave doors open or have poor insulation, it struggles more, which is normal for this type of unit.

The big downside is the noise. It’s rated around 65 dB, and you feel it. On high fan speed, it’s basically like having a vacuum cleaner in the corner, just with a more constant, lower-pitched hum. On medium and low it’s better, but still not what I’d call quiet. You can sleep with it on if you’re used to white noise or you wear earplugs, but if you’re sensitive to sound, it will annoy you. Sleep mode only slightly reduces fan speed and changes temperature slowly; it doesn’t magically turn the unit into a whisper-quiet device.

Heating performance is okay but not impressive. It’s good as a backup heater or to take the edge off a cold room in mid-season, but I wouldn’t rely on it as your only heating source in winter. It warms the air, but it doesn’t feel as efficient as a dedicated electric heater or a proper split heat pump. For a small room, it’s fine; for larger spaces or very cold climates, you’ll probably want something else as your main heat.

The dehumidifier mode is actually pretty useful. On a humid day, it pulled a noticeable amount of water from the air in a couple of hours and made the room feel less sticky. You’ll either use the included drainage pipe or occasionally empty the internal tank, depending on your setup. It’s not as quiet as a standalone dehumidifier, but it’s nice to have in one box. Overall, performance is good as long as you accept the noise and don’t expect it to cool a huge open-plan area. For a bedroom or office, it does what it’s supposed to do.

On paper, the COSTWAY 5 in 1 looks pretty stacked: 12,000 BTU cooling, heating function, fan mode, dehumidifier, sleep mode, 24-hour timer, three fan speeds, remote control, and a full window kit. The brand claims it’s good for 18–25 m² and lets you set the temperature between 16°C and 32°C. It uses R290 refrigerant (like a lot of newer units), has an energy efficiency rating around SEER 13, and pulls standard 220V mains power. No inverter, so it’s either running or not – no fancy variable speed compressor here.

In day-to-day use, the key thing is that it really is a multi-use unit. I’ve used all four main modes: cooling in summer, heating on a chilly evening, straight fan to just move air, and dehumidifying when the room felt damp. You switch modes from the top control panel or the remote. It’s pretty straightforward: big buttons, clear icons, and a simple LED display that shows temperature or timer. Nothing high-tech, but you don’t need the manual after the first day.

The cooling mode is the star here. From about 27–28°C down to 22–23°C in a 15–18 m² room, it took roughly 30–45 minutes with the door closed and curtains drawn. In a slightly larger living room, it took closer to an hour to feel properly cool. Heating works, but I’d call it more of a “support heater” than a main heating source. It takes the chill off, but if your house is poorly insulated and it’s really cold outside, don’t expect miracles.

Features like the 24-hour timer and sleep mode are functional but basic. Timer is handy if you want it to shut off after, say, 2 or 3 hours at night. Sleep mode slightly tweaks the temperature over time and drops the fan speed a bit, but the overall noise is still there. So yes, it’s genuinely 5-in-1, and everything works, but the standout is clearly the cooling. The other modes are more like bonuses rather than reasons to buy it on their own.