Air Purifiers Can Significantly Improve Indoor Air. These Are Our Favorites.

Your home should be a sanctuary, not ground zero for The Last of Us. These days, an air purifier is a must-have appliance — even more important than that expensive espresso machine. When choosing right model, here’s what actually matters:

Room size: An air purifier won’t be effective if it’s too small for your room, so size definitely matters. Always check the square footage rating in any purifier you consider purchasing. For best results, select a purifier rated for a space larger than your actual room, particularly if you have high ceilings. This approach provides a performance buffer and ensures more thorough air filtration, even when conditions aren’t ideal. While this might mean spending a bit more, the improved air quality is worth the investment.

The clean air delivery rate (CADR) and air changes per hour (ACH) are two other important metrics. The CADR indicates how quickly a unit can filter pollutants in cubic feet per minute, while the ACH tells you how many times the device can filter your room’s entire air volume hourly. If you suffer for allergies or asthma, you should look for at least 4–5 ACH.

Filter types

: An air purifier filter traps everything from dust, pet hair, and invisible allergens as they pass through the device. There are a few different types of filters you should know about.

• True HEPA: This is the gold standard of air purification, capturing at least 99.97 percent of particles as small as 0.3 microns, including dust, pollen, and most bacteria. A True HEPA filter is the move.
• HEPA-like: Here’s where it gets a little tricky. Some models have “HEPA-type” or “HEPA-like” filters, which may not meet the same rigorous standards and typically capture fewer particles.
• Activated carbon: This isn’t an essential part of an air purifier, but many models will pair HEPA filtration with activated carbon filters, which can absorb odors, smoke, and other pollutants that HEPA filters alone cannot trap.
• Pre-filter: Pre-filters act as the first line of defense in multi-stage filtration systems, capturing large particles like hair, dust, and lint before they reach the more expensive HEPA filter.

Maintenance and ongoing costs: Air purifiers are a lot more work than most people realize. They require regular maintenance and replacement filters to run efficiently. For instance, exterior vents and pre-filters need to be cleaned in regular intervals to prevent dust buildup that can restrict airflow. Manufacturers generally recommend basic monthly maintenance, with more heavy-duty cleaning every 3–6 months. Additionally, most HEPA filters should be replaced at minimum once a year, depending on usage and air quality. These can cost anywhere from $20–$100 or more. It can get expensive, so factor the ongoing cost — not just the initial price — before making a purchase.

Smart features: Some air purifiers take a simple approach, offering basic controls that focus on essential functionality. However, many modern models offer smart functionality, allowing you to remotely control your air purifier and see real-time air quality data. For instance, the Windmill Air Purifier supports an app that lets you set schedules and automations, turn on sleep mode, enable child lock, and see real-time stats, including your AQI (Air Quality Index, PM2.5).

These smart features are particularly helpful for those with mobility limitations, elderly users, or those with chronic health conditions. Smart features make it easy for anyone to control an air purifier from their bed or couch, adjust settings during the night, or make changes while away from home.

Noise: I’ve been using a few different air purifiers over the past few years, and they’re so quiet I hardly notice they’re there. Most models are generally whisper-quiet, operating at about 20–30 dB on low settings. Once the power ramps up, they can get fairly noisy at around 50–70 dB (70 dB is comparable to a running shower). Whether that’s tolerable depends on your own sensitivity to noise. For me, up to 50 dB is just fine at night when I’m trying to sleep. Some models have dedicated sleep modes that automatically reduce fan speeds to minimize noise and also turn off any distracting lights. Additionally, some air purifiers feature a white noise feature that produces a consistent, gentle sound that can help with sleep. So, not only do you get cleaner air, but you might actually experience improved sleep quality thanks to the background noise. It’s a win-win.