Winter is coming. Except this time around, it isn't just House Stark that should be worried about the pall of gloom associated with the onset of winter... All the great houses of our land ought to be concerned with the rising levels of airborne contaminants and pollutants. For all our UNESCO-rated achievements, India unfortunately ranks high in the top 20 cities globally with the worst air quality, and while you have no option but to don an N95/N99 mask when you're stepping out, the problem is exacerbated indoors. The same poor-quality air flows into our homes, remains trapped, and increases in pollutant concentration over time as it fraternizes with allergens, indoor smoke and fungal spores to create a deadly cocktail of what we believe is "fresh air".
It's time to buy an air purifier for your home.
Easy enough to say, less so to do. With brands having sensed the opportunity that more folks will wake up and smell the air, the market is flooded with air purifiers from domestic and international brands. So, how do you go about picking an air purifier that works for you and your air cleansing needs? Let's first arm you with some basics of the air purification process.
Understanding air purifier jargon
You'll need to first consider the size of the room where you intend to use the air purifier, ergo larger rooms (measured in square feet, plus you need to account for the room height) require larger air purifiers. It's much like picking an air conditioner... but in general, it's better to err on the side of caution and get one that is slightly larger in capacity, rather than scrimp and have a purifier that'll quite literally have to be running even to stand still. Most brands typically mention the coverage area so this is easy to check.
Placement is equally crucial, but that comes down to the air purifier's design. Most air purifiers have intakes on the side or the rear, so ample breathing space is important for them to be effective. Some, like the Dyson Pure Cool and Xiaomi 2S, have 360-degree filters that take in air from all sides and don't depend on ideal placement to work well. Same with outlet vents, some (like the BlueAir Sense+) have them on the side and others (like the Xiaomi series) disperse air upwards. You know the design of your room best, so keep these seemingly minor but fairly crucial design elements in mind when you're shopping.
Next, consider the air purifier's power, traditionally measured by its clean air delivery rate (CADR). Measured in cubic meters an hour, the CADR lets you identify how much air the purifier can filter in a given amount of time. Typically, the higher the CADR, the faster the air in your room will be cleansed. Just keep in mind CADR isn't a BIS-certified standard, so if a smaller unit is promising usually high CADR numbers, you should proceed with caution.
The type of filter an air purifier uses is important, with most preferred air purifiers opting at the very least for a HEPA (high-efficiency particulate air) filter which catches airborne particles, plus additional filters like a pre-filter (for larger particles) and activated carbon filters (for allergens, smoke, odors etc) for stuff that would otherwise pass through the HEPA filter. It's also worth remembering that depending on the brand and model, you pay upwards of Rs. 2,000 every six to eight months to replace the HEPA filter, which usually depends on how long you run the air purifier each day and pollution levels around your home. Pre-filters are usually washable, though.
Finally, you may want to look at other features, such noise levels – whether an air purifier has a night mode which dims the display and turns down the fans to produce less noise – and energy consumption levels (energy saving ratings and auto cut-off capabilities, again much like air conditioners). App connectivity, on-board displays with air quality index index (AQI) indicators displaying PM 2.5, PM10 levels are all bonuses.
With these features in mind, what makes our list of air purifiers this smoggy winter season? Here are our picks across various price points:
Xiaomi Mi Air Purifier 2S
Price: Rs 8,999
Much like with their phones, Xiaomi's been responsible for capturing the public imagination in this space with their feature-rich Mi Air Purifier range. The latest 2S variant sports a familiar squarish tower design, draws in air from intake holes across three sides and passes it through a three-layer (primary, EPA and activated carbon) circular air filter, finally pushing out clean air from the top. A circular OLED display shows real-time PM 2.5 levels (measured via a laser particle sensor) along with temperature, humidity, mode and Wi-Fi connection information. It pairs with the Mi Home app for hands-free remote control no matter where you are, and there's Alexa and Google Assistant support for the truly lazy.
Price: Rs 31,999
Blueair has air purifiers for rooms as small as 170 square feet all the way up to 1180 square feet - the Sense+ claims to capture 99.97% of airborne particles down to 0.1 microns in size, changing the air in a sub-200 square foot room up to 5 times an hour. It's equipped with motion sensors to change fan speed and can be controlled via the mobile app as well.
Philips Series 3000 AC3821
Price: Rs 37,995
Philips has a full range of air purifiers, starting with the Series 1000 AC1211 (Rs. 14,995) but the AC3821 offers something rather unique - a built-in humidifier to bump up humidity levels to up to 60%. A vent on the top pushes out clean air after it traps pollutants as small as 0.003 microns, and a digital display shows you current PM 2.5 levels.
Dyson Pure Cool
Price: Rs 44,900
Dyson's nailed the brief when it comes to form and function for this category, albeit at a steep price. It pushes clean air out of the bladeless fan which sits atop the 360-degree filter, which combines an activated carbon filter and a glass HEPA filter which weeds out microscopic allergens and contaminants as small as 0.1 microns. Control is via the magnetic remote control or via the full-featured Dyson Link app (over Wi-Fi), and a circular display on the front displays current AQI levels as well. In my experience, the Pure Cool was able to bring down PM 2.5 levels during the Diwali week from well over 200, to under 50, in a little under 20 minutes in a 200 square foot room.