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Silentnight Airmax 300 Dehumidifier review: our verdict on the dehumidifier designed for bedrooms

Mumsnet editor and mum-of-two Beccy put Silentnight's bedroom-friendly, colour-changing Airmax 300 Dehumidifier through its paces in her family home - here's what she thought.

By Rebecca Roberts | Last updated Jan 31, 2024

Price on writing: £50 | Buy now from Amazon

What we like

  • Straightforward to set up

  • Quiet white noise-like sound

  • Designed for bedrooms

  • Helps asthma symptoms overnight

  • Easy to empty tank

What we don’t like

  • Buttons are difficult to navigate in the dark

  • Only one dehumidification setting

Key specs

Type: Peltier Technology | Extraction amount: 300ml | Tank capacity: 1,100ml | Dimensions: 24 x 15.2 x 15.3cm | Weight: 1.17kg | Power: 23W | Cost per hour: 1p | Noise level: 35dB | Max room size: 15m² | Laundry mode: No | Warranty: 3 years

Related: The best budget washing machines under £500

How easy was the dehumidifier to set up and use?

Very, actually! In the box there’s the main unit, water tank, foot pad as well as a mains power adapter. There are only two buttons on the dehumidifier’s control panel: one for power, and one for the light. 

Turning the dehumidifier on and off is very simple, as you only need to press it once to turn it on, and once again to switch it off. Although, I have found you need to hold the button for a few seconds in order for it to turn on, which I only discovered during testing - this isn’t explained in the instructions. There is only one dehumidification setting, too. 

When turned on, the light begins to cycle through various colours - I believe there’s seven in total. You can select a colour to remain solid by pressing the light button, then press it once more to turn it off. 

One thing I found a little tricky was using it in the dark - the buttons on the control panel are flat, and quite difficult to feel around for when you can’t see! Particularly in the middle of the night.

Related: The best dehumidifiers, tried and tested

How noisy is the Silentnight Airmax 300?

Not very - it’s almost a very quiet, subtle white noise sound. As a mum of two I’m used to white noise in the background during the night, so, I didn’t find it to be disturbing. Relaxing, in fact. 

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Would you have it in your bedroom overnight?

Yes, this is what I’ve primarily been doing during testing. Our master bedroom is in a dormer, and our master bathroom is attached. While the bathroom has an extraction fan, there are no windows, and I find that upstairs can get a little humid if we’re not careful. So, we’ve primarily used the dehumidifier upstairs to prevent any excess moisture in the air while we sleep. 

How effective is it?

I have asthma and I noticed a difference in my chest in the morning after using the dehumidifier overnight. My chest can be affected by the colder weather. Combine that with the higher moisture in our dormer, then winter can be a particularly tricky time of year for my chest. But, since using the dehumidifier, this year it doesn’t seem to feel as bad after sleeping. 

In terms of moisture extracted from the air - I was pleasantly surprised to find quite a bit of water in there after just a few night’s sleep. After living in the desert for seven years, dehumidifiers used would often collect dust and sand in the air. So, it was also a nice surprise to find that the water collected wasn’t all that dirty in our bedroom! 

Read next: The best clothes steamers for crease-free outfits

Where did you use the dehumidifier?

During testing, we used it both in our open plan living space (lounge, dining, and kitchen) as well as our master bedroom. I didn’t dare test it in either child’s bedroom just in case they decided it was a new toy to play with. 

I also turned it on and plugged it in on our landing, which is where I have our clothes airer for laundry. Although, I didn’t find that it particularly helped the drying process. 

So, for me, it’s been most useful in our bedroom to remove extra moisture in the air from our bathroom as well as helping to soothe my asthma symptoms during the night. 

Related: The best steam irons to make light work of your laundry

How often did the Silentnight Airmax 300 need emptying, and was that straightforward?

According to the manual, the dehumidifier has a dehumidification capacity of 300ml per day, and the maximum capacity of the water tank overall is 1.1 litres. 

I tested the dehumidifier for a month and found it needed emptying at least once a week. This was very easy and straightforward to do. It only became full once, though, and I knew this as the indicator light began to flash yellow and the dehumidifier stopped. 

Once the tank is emptied, it’s very easy to slot the tank back into its original position and carry on using it. 

When it comes to cleaning, that’s equally straightforward. You only need to remove the water tank, give it a wipe and wash down, then place it back into position. 

Read next: The best budget dehumidifiers under £100 to keep your home damp-free

At £50 RRP, do you think it offers good value for money?

Personally, I’d say £50 is a little steep and I’d probably only want to spend around £30 for a dehumidifier of this size with its limited dehumidification controls. 

Final verdict

While I was impressed by the dehumidifier and it certainly made a difference to the air quality in my bedroom, it loses points due to the limited number of controls - there’s only one dehumidification setting - plus it can only be controlled by the control panel on the unit itself. It would be handy to have a remote or an app for this, too. 

The lights are a nice touch, but I don’t really want various colours in my bedroom. It might be nicer to have a white or warm light option, instead. 

Finally, it’s only quite small in size so would be better suited for an office or bedroom. I’d say it isn’t as powerful and effective if you have an open plan living space. 

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All Mumsnet product reviews are written by real people after weeks of research and testing. We work hard to provide honest and independent advice you can trust. Sometimes, we earn revenue through affiliate (click-to-buy) links in our articles. However, we never allow this to influence our coverage.

About the author

Rebecca (aka Beccy) is a writer, editor, and content marketing expert hailing from Leeds. Here at Mumsnet she commissions and creates content that’s designed to make parent’s lives easier.

Her career began back in 2010 when she took the helm of her university's student newspaper. Always encouraged to pursue a career in law, she instead found herself falling in love with writing and after graduating, moved to the Middle East to join the region's leading female- and family-focused expatriate website, ExpatWoman. Then after six years of sunshine and desert, she took a short career break to navigate motherhood (and a country move mid-pandemic) and is now Commercial Content Editor here at Mumsnet, working to bring readers industry-leading content from popular brands that aim to make parents' lives easier.

Spanning 13 years, her career has provided her opportunity to work closely with brands who are equally as passionate about all things female-focused, including some of best health, education, and wellness companies. It is thanks to her experience that she continues to enjoy working with much-loved brands by Mumsnetters that care about women and parents. As a mother herself, she knows all too well the trials and tribulations of modern-day parenting. Which is why she enjoys finding, learning about and sharing new products and companies that are specifically designed for parents, their kids and their families.

Offline, Rebecca can be found balancing life as a working mum of two toddlers. When she’s not at her desk, you’ll likely find her at her local playgroup, nearest soft play, or walking the dog up and down country lanes.