Hands-on review: Blueair DustMagnet 5240i

The 5240i is the middle-sized device in Blueair’s range of three DustMagnet air purifiers. It’s compact, like a small side table, at 52x22x22cm. You could easily pop a houseplant on it. Or sit it next to the sofa and leave the remote control and a cuppa on it. Just be careful with the cuppa or when watering the plant.

As the name suggests, it collects dust as well as allergens, germs, pollen and pet dander. Tech features include voice and app control, and even geofencing, so it saves energy when no one is home.

This model is designed to completely filter the air in a 48m² room every 30 minutes. That’s a large room: it can do a more typical 20m² room every 12.5 minutes. Its clean air delivery rate (CADR) is 226 m³ per hour for dust, 232m³/h for smoke and 238m³/h for pollen.

Below it in the range, in terms of price and model number, sits the DustMagnet 5210i (£329) which has the same specs and the same dimensions – it’s effectively the same machine, only with a plain white front instead of the grey textile.

Above it in the range sits the DustMagnet 5440i (£399) which is designed to completely filter the air in a 33m² room every 12.5 minutes or a 79m² room every 30 minutes. That would be ideal for large, open-plan spaces with more air to clean. It’s a bit larger at 65x29x29cm and its CADR is 391m³/h for smoke, 408m³/h for dust and 433m³/h for pollen.

Back to the DustMagnet 5240i on test, which boasts a Red Dot Design Award, an iF Design Award and the Quiet Mark for its 23-47dB sound level – quiet enough that you rarely notice it’s on.

The DustMagnet name comes from its bold claim to catch 99 per cent of airborne dust before it settles. It does this through a combination of airflow and positively charged pre-filters that attract the dust particles. The idea is that you’ll then need to do less cleaning in the room – although if it works as well as advertised, you’ll need to clean its pre-filters regularly.

It has two combination filter cartridges featuring Blueair HEPASilent technology, a combination of electrostatic and mechanical filtration. Filters are less dense and require less air pressure than traditional HEPA filters without a loss in performance – so the machines are quieter and more energy efficient. The filters also include activated carbon to remove tiny particles, such as odours and smoke.

The design is clever with the two combi filter cartridges top and bottom. The top one is set below the tabletop and the bottom one is lifted from the floor because of the legs, so both get good air flow.

Dust collection requires air flow, so it’s worth positioning a little away from the wall. We tested it in a bedroom; a room that’s prone to dust and where many hours are spent. The DustMagnet picked up dander (from the humans, from the cats) and it was felt that we could breathe easier.

Filter life is around 6-12 months, but this is based on usage: you get an alert on the machine and in the app when they need replacing. You can also subscribe for regular filter deliveries, if you prefer.

Unboxing feels more like furniture than tech. It’s in one piece and you just need to screw on the four legs. You do need to unwrap the two filters before use, but tabs stick out of the machine to tell you to do so. It’s completely intuitive and there’s no burning need to read the manual. Likewise, it’s easy to find the device on the Blueair app. Once in the app, you teach it your home Wi-Fi password and name it.

The app gives you oversight of air quality. The DustMagnet’s built-in air quality sensor sets its fan speed (if it’s on the Auto setting) and a five-step coloured LED on the front of the machine gives a visual indicator of air quality. It also reports to the app: you get a graph of PM2.5 levels (particles with a diameter of no more than 2.5 micrometres).

Pricier Blueair machines track more particle sizes. For example, HealthProtect models give graphs of PM1, PM2.5, PM10 and tVOC as well as temperature and humidity. This wider range of sensors is well suited for scrubbing the air in kitchens, where cooking and cleaning put smaller particles into the air.

The DustMagnet has three fan levels, an Auto setting and also a Night setting (quiet, fewer LEDs). You can tap a button on the device to cycle between these or control them via app. We found the Auto setting the simplest, though you can turn the fan up high when you know you’re going to kick up a lot of dust (e.g. cleaning, DIY, tidying).

The app also features scheduling, which is a great way to curb ‘vampire device’ wastefulness. Simple schedules can be set up to ensure you’re not cleaning the air when no-one’s home and that it’s on Night mode every night. If your movements aren’t predictable, the Blueair app also offers geofencing. The app can use your phone location to sense when you go away and go into standby mode, then start up again when you’re nearly home.

These both worked well, although we had some difficulty getting the Blueair to work with a Google Home setup for voice control. It worked better with Amazon Alexa, which offers app and voice control.

Most importantly, does it really pull dust out of the air? Yes, you definitely need to do less dusting when the Blueair is in operation. This is confirmed when you clean the fine mesh pre-filters. Sadly, though, it doesn’t abolish dusting completely. It pulls in lighter dust particles before they settle – those motes that float in the air and get sucked in easily – but not heavier dust that settles fast. You’ll still have to dust, just less often.

The design supports the job. It looks like a piece of furniture, so you won’t feel the need to hide it – which is good, because it’s more effective at sucking up dust if it’s not hidden in a corner.

£349 blueair.com

Alternatives

Ikea Starkvind

Affordable, clever side table with built-in air purifier (as opposed to an air purifier with a bit of a tabletop on it). Auto detects PM2.5 and selects from five fan speeds. Optional gas filter for smaller particles. Works with Ikea Home app for smart and voice control. For rooms up to 20m²; CADR 45-260m³/h.

£199 ikea.com 

Coway Airmega 300S

A pricier, more powerful air purifier than the Blueair DustMagnet, with multiple filters including activated carbon. The stylish design is similar, on legs, but the top doesn’t double as a table – it’s an air intake instead. Recommended for rooms up to 149m², which is frankly the size of a house; CADR 575m³/h.

£499 coway.com

Blueair Blue 3210

The smallest and most affordable model from Blueair. Unlike older models, there is an air quality (PM2.5) sensor, so it can set its level automatically, but there’s no Wi-Fi or app control. Unlike the DustMagnet, the fabric serves a purpose: it’s a washable pre-filter, which you can replace with a different colour. For rooms up to 17sqm; CADR 163-210 m³/h.

£179 blueair.com