YEAR GUARANTEE - We've got you covered. Register your product for a free 2 year guarantee and total peace of mind. Even without all the smart stuff, this is an easy purifier to use. Clear indicators show the current mode and power setting, while a central ring glows blue through to red, depending on the current air quality readings. You can pretty much leave it on the Automatic setting and let it do its thing. It can get a little noisy at its highest speeds, peaking at 52.7dB in Turbo mode, but we measured a very reasonable 28dB in Sleep mode. We’re not sure how well that works in practice, but the UA-HD40U-L is impressively efficient at filtering out impurities and very quiet at its automatic and low-power settings. A strip on the top turns from red to orange to green to indicate the current air quality, and there’s a humidity readout so you can monitor humidity levels, although both this and the “ion shower” feature can be turned off if you just want air purification. Well designed and easy to use, this is a great air purifier for smaller rooms. What we really like about this purifier, however, is that it’s both effective and pretty quiet about it. At full tilt, it’s as noisy as most rival air purifiers, but in its sleep mode you’d struggle to hear it above ambient sound levels – we measured the output at just 31dBA. In our deodorant spray test, the H-Purifier 500 got the PM2.5 concentration down to safe levels within two minutes and eight seconds, and Hoover’s three-filter purification system has been approved by the Allergy UK charity. We’re not 100% sure about the option to add essential oils to the airflow, but the options include an H-Biotics bottle that adds probiotic “good” bacteria to the atmosphere. All in all, it’s a superior purifier that’s perfect for mid-sized and larger rooms, with a price tag that won’t leave you gasping.

LED DISPLAY AND LIGHTING - Cleaner air is made simple with this easy-to-use air purifier. This model offers a timer option for 2, 4 or 8 hours, giving you complete control. It also features colour-changing LED lighting to suit any setting. With an intuitive touch control panel and three speed settings, it's simple to operate and easy to adjust the air filtration to suit any room. The LED display offers a timer option for 2, 4 or 8 hours, as well as a handy Filter Change Reminder. There’s even a night mode to dim the LED display and slow down the fan speed, so you can enjoy uninterrupted sleep while purifying the air around you. Key specs – CADR: 280m³/h; Max room size: 35m²; Power settings: 4; Dimensions (WDH): 25 x 25 x 45cm; Weight: 3.8kg; Filter replacement indicator: Yes; Warranty: 2 years

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It’s just as good as an air purifier too, though its CADR rating is slightly below that of the purifier-only Pro P2. In tests, it took PM2.5 levels from a maximum 411 micrograms per square metre to 25 in 135 seconds, bringing it down to double figures in just over a minute. Again like the Pro P2, it’s quiet, with the noise barely noticeable at the lowest speed in purifier mode. Left on Smart mode, with the front-facing display turned off, all but the lightest sleepers should be able to sleep through. LED Display and Lighting– Cleaner air is made simple with this easy-to-use air purifier. This model offers a timer option for 2, 4 or 8 hours, giving you complete control. It also features colour-changing LED lighting to suit any setting. Please note some larger products are delivered to kerb-side (the street outside your home), it is at the drivers discretion if they can deliver the item to another location on the property.

Key specs – CADR: 240m³/h; Max room size: 20m²; Power settings: 4; Dimensions (WDH): 51 x 19 x 53cm; Weight: 5.9kg; Filter replacement indicator: Yes; Warranty: 1 year Air purifiers use different kinds of filters to do their job – usually, a large, washable, reusable pre-filter to collect bigger particles, plus a finer filter, which is usually a disposable high-efficiency particulate air (HEPA) filter. The length of time this lasts varies, but on average expect it to need replacing every six months (or fewer if you use the machine less). It’s the HEPA filter that catches all the tiny airborne nasties, and these are capable of catching particles as small as 0.3 microns, which is more than three times smaller than a cigarette smoke particle. Noise is another factor – you don’t want to replace one irritation (allergies) with another (the sound of a jet plane in your room). For many, the hum is something that doesn’t bother them, but some purifiers can get very noisy. It’s also worth remembering that, while some machines are quiet on their lowest setting (where they’re often at their least effective), they might be loud on the fastest (where they’re working at their best). Otherwise, this has the same advantages as the smaller version: effective three-stage filtering, a built-in humidifying function and Sharp’s Plasmacluster ion technology, which – while it sounds like a weapon from a Halo game – works to kill odours, bacteria and mould. While the Vax PureAir 300 gives you even more airflow and covers larger rooms for less, the Sharp hits a sweet spot for price, performance and features, making it a great mid-range purifier for mid-sized rooms. It’s really designed for small spaces of around 10m², but we found its performance better than the 80m³/h CADR might imply. Spraying antiperspirant into a small room with the purifier at maximum speed, the Clean Air Compact brought PM2.5 particulates down to safe levels within three minutes and six seconds. At that speed it’s fairly noisy, with sound levels reaching around 48dBA, but in general use the lowest setting will be fine, and this takes the noise levels down to 36.2dBA, where the sound is noticeable but hardly aggravating.CLEAN AIR PRO - This compact model is perfect for small to medium rooms up to 14m², such as your home office, bedroom or living space. The sleek, contemporary body is designed to fit seamlessly into your surroundings. If you wish to return your item to Robert Dyas, you can do so by the following method: 1. Request a Collection via Robert Dyas Customer Services Some purifiers have a built-in timer. This can be really useful if you want your machine to come on a few hours before you get home, or if you want to turn it off automatically at night. CLEAN AIR COMPACT - This compact model is perfect for small rooms up to 10m², such as your home office, bedroom or living space. The sleek, contemporary body is designed to fit seamlessly into your surroundings.