Smart Air Purifiers: How to Buy the Best Option for Your Home or Office

With air quality being important, especially in big cities, more and more people are using air purifiers to prevent allergies and even kill bacteria and viruses. In this buying guide, we introduce you to some of the most popular models on the market and explain the important features you need to know.

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June 8th update: With the recent wildfires in Canada causing air quality levels to drop to "unhealthy" levels, specialists suggest staying indoors as much as possible with the doors and windows closed, especially since surgical and cloth face masks—like those recommended during the pandemic—do not protect from fire smoke.

In the current situation, air purifiers can help improve air quality indoors but it is important to seal off doors and windows to avoid smoke from entering the room. It is also important to check the specifications to see whether the air purifier is capable of cleaning the room's volume (or area, as brands usually rate the room coverage) and check if the filters need to be cleaned or swapped.

If you already have an HVAC system, similar considerations apply, and it is not strictly necessary to buy an air purifier if you have a well-maintained HVAC.

For more information on air quality in US cities, check AirNow.gov. For Canada, you can check the air quality index for many cities in this Government's hotsite.

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This way, you'll know everything you need to know about the HEPA filter, CADR cover, PM2.5 particle sensors, and more to choose your connected air purifier properly.

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Smart air purifiers compared
Product	Dyson PH04	Xiaomi Smart Air Purifier 4	Xiaomi Smart Air Purifier 3H	Phillips 3000i	Ikea Starkvind table	Ikea Starkvind
Picture
Filtration method	HEPA filter Activated carbon catalytic filter	Particle filter Activated carbon Electrostatic charge	Particle filter Activated carbon	HEPA filter Activated carbon	Particle filter Activated carbon (optional)	Particle filter Activated carbon (optional)
Recommended area	40 m³	48 m²	45 m² 484 ft²	135 m² 1453 ft²	20 m² 215 ft²	20 m² 215 ft²
Filtration rate	-	400 m³/h 235 CFM	380m³/h 223 CFM	520m³/h 306 CFM	260 m³/h (high, 153 CFM) 50 m³/h (low, 29.4 CFM)	268 m³/h (high, 158 CFM) 55 m³/h (low, 32.3 CFM)
Sensors	Particle sensor (PM 2.5 and PM 10) Gas sensor ( VOCs, nitrogen dioxide) Formaldehyde sensor Temperature & Humidity	PM2.5 PM10	PM2.5 PM10	PM2.5 TVOC	PM2.5 PM10	PM2.5 PM10
Filter lifetime / price	12 months $75,00	6–12 months €59.90	6–12 months $49.99 / €39.99	up to 36 months €69.99	6 months $15 $20 (activated carbon filter)	6 months $5 $20 (activated carbon filter)
Power consumption	40 W (max) 1 W (standby)	n/a	38 W	55 W	33 W (high) 2 W (low)	33 W (high) 2 W (low)
Noise level	61 dB (max) 32 dB (min)	64 dB (max) 32.1 dB (night mode)	64 dB (max) 32 dB (low)	56 dB (turbo) 15 dB (sleep)	53 dB (high) 24 dB (low)	53 dB (high) 24 dB (low)
Amazon Alexa	Yes	Yes	Yes	Yes	Yes	Yes
Apple HomeKit	Yes	No	No	No	Yes	Yes
Google Assistant	Yes	Yes	Yes	Yes	Yes	Yes
Other ecosystems	Dyson Link app	Xiaomi Home app	Xiaomi Home app	Philips Clean Home+ app	Ikea Home/Trådfri	Ikea Home/Trådfri
Dimensions (W x D x H)	155 × 210 × 923 mm	21 x 21 x 22 inches 540 x 540 x 550 mm	20 x 7 x 21 inches 510 x 190 x 530 mm	11.4 x 11.4 x 25.4 inches 290 x 290 x 645 mm	9.45 × 9.45 × 20.47 inches 240 x 240 x 520 mm	9.45 × 9.45 × 20.47 inches 240 × 240 × 520 mm
Weight	8,29 kg	9.3 kg (20 lb 11 oz)	7.57 kg (16 lb 13 oz)	6.8 kg (15 lb)	4.8 kg (10.6 lb)	4.6 kg (10.1 lb)
Rating	Read the Dyson PH04 review			Read the Philips AC3033/10 review		Read the Ikea Starkvind review
Offers*

Table of Contents:

• Why buy a smart air purifier instead of a non-smart model
  • Sensor types: PM10, PM2.5, NO2, TVOC
  • Smart home ecosystems: Alexa, HomeKit, Google Assistant
• Filtering capabilities
  • Filter types: HEPA, activated carbon, ionic, UV light
  • Maximum coverage area and CADR
  • Filter replacement costs

Why choose a smart air purifier instead of a regular one

Air purifiers are appliances that are not necessary 24h per day for most people, and some may even require them for short periods of time during specific months of the year. In those cases, it might be worth considering buying a smart model.

Armed with sensors and with the option of being controlled by a mobile app, smart air purifiers can be set to function only when the pollutants levels are harmful or when there are people in the house or room, potentially saving power.

Sensor types

One of the must-have features of a smart air purifier is an array of sensors to automatically detect the level of pollutants, and adjust the fan accordingly. Sensor data can also be sent to an accompanying app, where you can check for air quality.

Air purifier applications can not only report the overall quality of air, but also display statistics, historical data, forecasts, and present the status of the different kinds of pollutants:

• NO2 — nitrogen dioxide — gas produced by burning fossil fuels (vehicles, power plants, etc).
• PM1.0 — particulate matter up to 1 μm — 50x smaller than the diameter of a human hair.
• PM2.5 — fine particles, smaller than 2.5 μm — metals, organic compounds, combustion smoke.
• PM10 — inhalable particles, smaller than 10 μm — pollen, spores, mold, dust.
• VOCs — volatile organic compounds — responsible for odors (good or bad), are produced by things such as paints, or incomplete combustion.

Smart-home compatibility

Another feature of smart air purifiers is their compatibility with smart home ecosystems and voice assistants. Depending on the model, the device can be integrated into defined schedules—turn on filtering before sleeping when the lights dim, turn it off in the morning when the curtains go up, etc.

One thing to look forward to in the future is compatibility with the Matter smart home standard, which promises to simplify control and integration between devices. Apple, Amazon, Google, Oppo, Samsung, Ikea, Signify, Tuya, and other heavyweights are among Matter supporters.

The Matter standard was launched in October 2022, but the first release doesn't have support for air purifiers. The CSA (Connectivity Standards Alliance, the group responsible for the standard) however, already hinted at new product categories for future releases.

Another thing that many smart air purifiers offer is an accompanying app that can be used to remote control, monitor air quality, adjust fan speed and noise, and also set reminders for buying new filters.

Different types of filters found in air purifiers

HEPA filters

HEPA is a type of air filter that can remove at least 99.95% of dust particles, bacteria, pollen, mold, and other airborne particles between 0.3 and 10 micrometers (µm) in diameter.

Sometimes, manufacturers will report an additional number, known as the efficiency rating. In general HEPA filters are classified as either H13 or H14 in the European Union, with the latter defining filters capable of retaining more than 99.995% of particles within that size range.

Other companies advertise products with terms like “HEPA-like/type/style” or “99% HEPA”, but that is basically a meaningless classification for filters that do not pass the HEPA requirements, or at best haven’t been properly tested.

Activated Carbon 

Besides removing particulate matter from the air we breathe, some filters also promise to remove odors and gases. That can be done using an activated carbon filter, capable of removing VOCs, odors, and gases, such as NO2.

Also called charcoal filters, they are made using a porous material, and work using a process called adsorption—in which the pollutant stick to the carbon molecules, but does not get absorbed.

Ionizers

Ionizer filters work by charging the room particles to make them easier to attract and capture by the filter or make them fall to the ground. While it may help with smoke particles, for example, the feature liberates ozone as a byproduct, which depending on the level produced can cause lung irritation.

UV light

Some air purifiers also include a UV light to destroy pollutants. Also called ultraviolet germicidal irradiation (UVGI), the feature tries to destroy biological matter, like bacteria, mold, and viruses by damaging their cell structure or protein shell, even inactivating some viruses.

Room size coverage and CADR

Keep in mind which room(s) you expect to use the air filter on and compare the overall room volume with the manufacturer’s recommendation. Some models list the American standard CADR (clean air delivery rate) which notes the cubic feet of air per minute (CFM) filtered in a 1000 ft³ (28.5 m³) room.

Depending on the region, air purifiers are advertised with their filtering rate in cubic meters per hour (m³/h) or CFM. Note that the value shown is the maximum offered by the device, and features like “silent mode”, “night mode”, or power-saving options will lower the filtering rate.

Hidden costs: filter replacements

One often overlooked detail when shopping for an air purifier is the filter cost. Expect to change filters once or twice a year, with many models notifying when it is time to replace the filter—some even allow customers to order a replacement from the companion app.

Filter costs are usually proportional to the capabilities—particulate/HEPA filter and/or activated carbon—, and some companies even sell the different components separately like Ikea, with the particulate and activated carbon filters sold on their own for the Starkvind models.

Also, similar to what happens with coffee pods, replacement filters for bigger brands are usually easier to find than components for some niche companies only found on the Amazon marketplace. Some of the most popular models even have third-party filters available, but be aware that their usage may void the device warranty!

What did you think about this overview of smart air purifiers? Do you use one? What are the most important features for you? Share your opinion in the comments below.

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Article updated in June 2023 with notes regarding the wildfires in Canada and the resulting air pollution in northeastern US cities.

Source: EPA, (2)