My home office gets unbearably hot in the summer, but this surprisingly quiet Dreo portable air conditioner has been an utter gamechanger

With summer heatwaves more commonplace, it's no wonder that more and more people are looking for the most effective ways to stay cool at home.

And one of the most effective has to be a portable air conditioner. But when these appliances can set you back hundreds of pounds, it helps to have a deeper insight into how well it works, what it's actually like to use, and ultimately whether it's right for your home.

I've tested the Dreo 318S Portable Air Conditioner in my own home over a few weeks, including during a heatwave. This is how I got on and whether I think it's worth your money.

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In a nutshell

It's hard to beat a portable air conditioner when it comes to cooling your home, but not all portable ACs are created equal, with size, noise, looks and cooling capacity all varying between brands.

Fortunately, the Dreo 318S portable air conditioner ticks multiple boxes, which makes it a very good buy indeed. With a cooling capacity of 7500BTU, it's best for smaller spaces (up to 20m2) and as such it's quite a compact for a portable air conditioner. It's really effective too, quickly dropping the temperature in my home office from 24°C to 20.5°C in about 20 minutes. It also does it relatively quietly too. Portable ACs are not whisper quiet like some fans are in their lower speeds, but the Dreo 318S is definitely quieter than portable ACs I've used in the past, that sounded like a bin lorry in the house.

My only niggle really, is the length of the exhaust tube that you use to vent it out of the window, it felt a touch too short and so it was a bit tricky to get it effectively vented out of the window.

Sarah Handley

As well as being Ideal Home's Renovation Editor, I also look after all of the website's heating and cooling content, which means I'm well versed in what it takes to keep your home a comfortable temperature year round and how you can do that in the most energy efficient way possible. I tested the Dreo 318S portable air conditioner in my 1970s three-bed home for more than three weeks during a warm summer. I used in my 12m2 home office. Find out more about how we test portable air conditioners.

Specification

• Cooling capacity (BTU): 7500BTU
• Recommended room size: Up to 20m²
• Noise levels in cooling mode: 62dB
• Dimensions (W x H x D): 38.5cm x 63cm x 35.5cm
• Weight: 22.5kg
• Wattage: 800W
• Functions: Air conditioner, fan, dehumidifier
• Other features: Timer, 'night' mode, remote control
• Window kit included: Yes

Unboxing, setting up and first impressions

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With a weight of 2.5kgs, it was tricky to manoeuvre the package from the front door further into my house, especially as I was by myself when it arrived, so I'd definitely recommend waiting until you have an extra pair of hands. Fortunately, I have laminate flooring and managed to push the box upright into my living room.

I loved that the cardboard packaging had instructions on the outside of exactly how to unpack it safely. Once I'd removed the heavy duty plastic bands, I opened the top of the box to remove the accessories, and then I just needed to lift the cardboard sides away from the base. That's all very easy and requires no heavy lifting. But you will need to lift the appliance out of the base packaging (which is polystyrene and cardboard), and that is not easy to do single handedly, especially when you need to keep the portable AC upright.

There is plastic packaging included, which can't be recycled at home, which is a shame.

Once the portable AC is out of the packaging, that's half the battle won. Then it was time to set up the window kit. You get two window kits in the box, one for sliding windows and a universal fabric one that should work on most other types of window. To set this up takes a bit of time as you have to stick Velcro all around the window frame and again around the casement. I'm very glad I set this up before the heatwave hit as it takes about 10 minutes. Then I needed to attach the fabric to create the window seal, which probably took me another 10 minutes or so.

I then moved the portable AC into position (it's on wheels so this is really easy if you have hard floors, although it's a little bit more difficult on carpet). If you want it upstairs, definitely do not attempt to do it alone. I set it up in my home office, which measures roughly 12m2. When the exhaust hose is attached, it doesn't sit flush against a wall (you need space around it for adequate air flow, so you'll need to clear a suitable space for it to do it's thing). As you need a window kit in order to vent it out of the window, if you want to be able to move it from room to room, you will need to move the window kit along with it. It's relatively easy to move from room to room on the same floor, but it's heavy to take up and down stairs, so I found it easier to leave it in a specific room.

Once in position, I used needed to attach the exhaust hose to the back of the unit, and vent it out through the window seal (although there is also some accessories to vent it through the wall if you would prefer, although remember this is a permanent change. This should have been easy, but the length of the exhaust hose, combined with the height and depth of my window cill, meant that it only just reached to the window.

What’s it like to use?

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Once the window kit and exhaust hose were set up, I decided to hold off on setting up the app control and instead went straight in with the remote control to get it up and running. The remote control is pretty easy to use, although I did find it helpful to have the instructions nearby to start with.

I tried it in fan mode first, which is fine, but not a patch on the best fans out there. There are four speeds (low, medium, high, auto) and I found that if you have the louvres on swing mode, it'll feel like a natural breeze. It's not quite though, even in the lower speed. But realistically, I view this as a bonus function that I'm not likely to use that often. I have other fans that are quieter and more compact, and they would be by go-to for air circulation.

The pièce de résistance is definitely the cooling mode. When I first switched to this mode, I was a bit confused as it defaulted to Fahrenheit which, to be honest, does not compute in my brain. Is 75°F hot or cold? Who knows? While it wasn't initially obvious how to switch it to °C, it fortunately does explain how to do it in the instructions (long press the + and - buttons). I found it best to do this on the remote as when I did it on the unit itself, it went back to °F when I changed a setting. But doing it on the remote changed it to default to °C.

I'd put the portable AC in my home office, and measured a temperature of 24°C, and turned on the cooling mode with a target temperature of 18°C. I then shut the door and left the room for about 20 minutes. When I went back, my thermometer was showing 20.5°C and it felt much cooler and fresher in there. I'd left the louvres on swing too which I think helped distribute the cool air more effectively. It was blissfully cool.

Once I'd got the settings to my specific liking, I appreciated that the unit remembered them when I came back the next day and turned it on again.

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I was initially surprised by how quiet the Dreo 318S was (bin lorry being my yardstick), it's not silent, but it's definitely not obnoxiously loud. Using my decibel reader, I clocked it at 59dB in the lowest fan speed, and at 62dB at top speed, which is the equivalent of between gentle background noise and a chat with friends. I could definitely cope with that in a bedroom setting! It also offers a sleep function in cooling mode, which not only mutes all beep sounds, turns off the display and decreases louvre swing to reduce noise, but also gradually increases the temperature to compensate for body temperature lost during sleep (which you can customise in the app).

In addition to fan mode, this portable air con also has a dehumidifier mode. But given I'm fortunate to not suffer with moisture issues in my home and it wasn't particularly humid when I was testing, this isn't a mode that I would use often. However, if your home does struggle with excess moisture, then the dehumidifier mode that can extract 2.5L per hour, will be right up your street. In that mode, it does require continuous drainage, so bear that in mind.

After using it for a couple of weeks via the remote control or on-board control panel, I decided to set it up for app control. It was easy enough to download and register on the Dreo app, taking only a minute or so. You can do exactly what you can do on the remote through the app, with the added extra of being able to set up schedules.

Running costs

Using between 800W and 2.2kW of power, this Dreo portable air conditioner will cost you between 21 and 57p per hour to run, based on the July 2026 energy price cap.

To help reduce running costs, the appliance does have a customisable Eco mode, where you can adjust the compressors start/stop frequency from 10-30% to reduce energy consumption. Bear in mind though that this will affect it's cooling capacity.

Cleaning and maintenance

To keep the Dreo318S in good working order, it's important to keep it as free from dust as possible. Wiping over the exterior with a dry cloth regularly is a good start, and the instructions state how to clean the air filters and remove any build up there.

Maintenance will largely come down to the removal of excess water which will vary depending on the mode you use. If you only use it in cooling mode, then DREO's patented algorithm, sensors and pump evaporate excess water automatically eliminating the need for drainage in environments of up to 90% humidity. This was great for me as I only really need to use it for cooling purposes.

However, if you use it in dehumidifier mode, you will need to drain it continuously whenever that mode is selected.

Who should buy this product?

If you're looking to keep a smaller room cool in the heat, then the Dreo 318S will be ideal. It cools quickly and effectively and is easy to use. While it's not exactly whisper quiet, it's quiet enough to be used in a home office or bedroom with ease, and the Sleep Mode will help reduce any overnight distractions.

It's a good option too if you want an air conditioner and dehumidifier in a single unit.

However, at 7500BTU, this portable AC won't suit you if you are looking to cool a larger space. Fortunately, the DREO 516S portable air conditioner (£599.99 at Amazon) offers all the same functionality in a 12,000BTU powered unit, which can serve rooms up to 37m2.

While the Dreo 318S portable air conditioner is near the low-mid point in terms of price range, if you want something more affordable you could consider the Vonhaus portable air conditioner. Although for a lower price, you will have to make a bit of a sacrifice on quietness.