The Dreo Air Purifier 539S is a basic, budget-friendly air purifier intended for small to medium-sized spaces. It features a three-stage filter system with a pre-filter, primary HEPA-rated layer, and activated carbon for odor reduction. Beyond that, it has an air quality sensor for real-time fan speed adjustment and Wi-Fi connectivity so you can change settings, set operating schedules, or check filter status through your smartphone. Its companion app also features Amazon Alexa and Google Assistant integration, allowing you to control the Dreo using voice commands.
Our Verdict
The Dreo Air Purifier 539S is a good choice for pet owners. Its washable pre-filter keeps pet fur from clogging its primary filter, which is also up to the task of handling finer pet allergens like dander. Its clean air delivery rate (CADR) is sufficient for large bedrooms and medium-sized living areas. It's quieter than most other models at its highest fan speed, though it's still liable to annoy more noise-sensitive pets in this configuration. Turning things down to a lower, quieter setting effectively restricts its use to smaller bedrooms or home offices and makes it very discreet. The onboard Wi-Fi connectivity also lets you check the air quality, adjust the fan speed, or turn it off if you think it might disturb your pet, even while you're away for the day.
Nearly inaudible at low fan speeds.
CADR at max speed is sufficient for medium-sized spaces.
In-app connectivity allows you to run the device while you're away from home.
Air quality sensor mode minimizes the need for hands-on monitoring.
Max CADR is insufficient for big, open-concept areas.
CADR at low, quiet fan speeds is on the lower end of the scale.
The Dreo Air Purifier 539S is great for bedrooms. It's small enough to keep on a dresser or nightstand. While it's far from class-leading in clean air delivery rate, its performance is still sufficient for most bedrooms at lower fan speeds, especially if you plan to run it overnight. It features an air quality sensor mode that automatically increases its fan speed as needed, so you don't need to wake up to adjust it if your air quality dips while you're asleep. It's also practically inaudible at those lower fan speeds. While the dimmable display minimizes distractions in nurseries and bedrooms, it can't be turned completely off, unlike many alternatives.
Compact enough to fit on a dresser or nightstand.
Nearly inaudible at low fan speeds.
Air quality sensor mode minimizes the need for hands-on monitoring.
CADR at low, quiet fan speeds is on the lower end of the scale.
Display can only be dimmed, not turned off.
The Dreo Air Purifier 539S's particle filtration rate is decent. Its maximum clean air delivery rate is sufficient for medium-sized rooms, such as apartment living rooms or dining areas. That said, it'll take an unreasonable amount of time to improve air quality in bigger open-concept spaces compared to more powerful alternatives.
CADR at max speed is sufficient for medium-sized spaces.
Max CADR is insufficient for big, open-concept areas.
The Dreo Air Purifier 539S has a compact footprint. Its lightweight, low-profile design allows you to set it on a dresser, desk, or countertop. This makes it a good fit for tighter rooms where floor space is at a premium.
Compact enough to fit on a dresser or nightstand.
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Differences Between Sizes And Variants
The Dreo 539S is available in two colorways: Black and White. We bought and tested the Black variant, and for those interested, here's the product label. Also note that you can buy a separate variant of this air purifier, simply called the Dreo 539, without Wi-Fi connectivity.
Let us know in the comments if you come across another variant of this air purifier so that we can update our review.
Popular Air Purifier Comparisons
The Dreo Air Purifier 539S is a basic air purifier for those shopping on a budget. It's a solid option within its price bracket; while it's likely to struggle in large, open-concept areas, it still outperforms alternatives like the Levoit Core 300S in terms of clean air delivery rate, all the while making less noise, making it a good option for small- to medium-sized spaces. Within Dreo's lineup, it sits above the more compact Dreo Air Purifier 338S and represents the more compelling buy overall; the 338S is only slightly smaller but offers far less in terms of performance. The 539S is also respectable in terms of features; unlike the PuroAir 240, it features Wi-Fi connectivity so you can run the device or monitor air quality while you're away from home.
If you're shopping for alternatives, see our recommendations for the best small air purifiers, the best quiet air purifiers, and the best air purifiers for bedrooms.
The Dreo Air Purifier 539S is better than the Levoit Core 300S. The Dreo has the Levoit beat in terms of clean air delivery rate, delivering the same level of air quality about 20% faster in an equivalently sized space. That gap narrows when both units are set to lower, quieter speeds, though the Dreo still pulls slightly ahead in this respect. The Levoit does have a small advantage in that its display can be turned off completely, rather than only being dimmable, as with the Dreo.
The Dreo Air Purifier 539S is more versatile than the PuroAir 240. The PuroAir is only slightly smaller, but the Dreo holds a significant advantage in performance, with a clean air delivery rate that's more than 40% higher at both its highest fan speed and at lower settings, making it a better option for larger spaces, or smaller bedrooms and nurseries where you'd want to improve air quality in a hurry. More than that, the Dreo runs more quietly at its lowest fan speed, and unlike the PuroAir, it features onboard Wi-Fi so you can operate the unit with your smartphone.
The Blueair Blue Signature Small and Dreo Air Purifier 539S are evenly matched compact air purifiers, with both units providing near-identical clean air delivery rates. The Blueair is the better choice if you're looking for something with a subtler impact on your daily life; you can set small items on its flat top, and it runs noticeably quieter at both its highest and lowest fan speeds. That said, the Blueair features an always-on particle ionizer system. While said system's ozone production levels are certified to fall within safe limits, the Dreo might still be the better choice if that remains a risk factor for you or someone else in your household.
The Dreo Air Purifier 338S and Dreo Air Purifier 539S have very similar feature sets, but the 539S is the more powerful model. It has a substantially higher clean air delivery rate, allowing it to filter the air faster and handle larger rooms more effectively. The AP338S is smaller and runs a little more quietly, making it easier to place in a bedroom or office where extra cleaning capacity isn't necessary. Both offer companion app support, automatic air quality monitoring, adjustable ambient lighting, and an app-only Turbo mode, so the choice mainly comes down to room size and how much cleaning performance you need.
Test Results
You can operate this unit via the Dreo companion app, which lets you set operating schedules, monitor air quality, and check filter status. You can also use the app to tweak the brightness of its controls on a granular level.
This unit features four conventional fan speed settings, a Sleep mode for low-noise, low-speed operation, and a Turbo mode for larger spaces, which is only accessible through the Dreo app. Beyond that, its air quality monitoring system also allows it to automatically change its fan speed in real time when it's set to its Auto mode.
If you want an even more in-depth look at the 539S' features and functions, you can also access its user manual online.
The Dreo Air Purifier 539S features a fairly conventional 3-stage filtration system consisting of a pre-filter for trapping dust, hair strands, and other larger particles, a HEPA-rated primary layer for standard allergens like pet dander, pollen, and fine dust, and a pellet-type activated carbon layer to reduce odors. That said, the carbon layer doesn't contain a high enough amount of carbon media to make a significant impact on volatile organic compounds (VOCs); as we discovered in our R&D investigation on the topic, achieving a meaningful reduction in VOC levels requires significantly larger quantities of this material than what most household air purifiers provide.
The pre-filter should be wiped down with a clean cloth to dislodge any stuck-on debris every two to four weeks, depending on your home's air quality. Meanwhile, the primary HEPA/carbon filter should be replaced every six to eight months. Replacements can be purchased from Dreo's website.
It's worth noting that Dreo's marketing material states that its filter's HEPA rating was achieved through independent testing, but doesn't cite a specific testing standard, such as IEST-RP-CC007, IEST-RP-CC001, or EN 1822.
This unit's clean air delivery rate at its highest fan speed is decent. It outperforms the smaller, weaker
Dreo Air Purifier 338S in this respect, and can handle smaller living rooms in apartments, or large bedrooms and offices, all by itself.
It's worth noting that Dreo's advertised clean air delivery rate is AHAM-verified and, as a result, closely aligns with our own test results. This is something of a welcome surprise, as most manufacturer performance claims tend to be overly optimistic.
In a low-noise configuration in fan speed 2, the Dreo Air Purifier 539S's clean air delivery rate is adequate overall. It'll struggle to clear the air in most living rooms or open-concept apartments, especially if you're doing something that introduces a lot of airborne contaminants, like cooking or grooming a pet. That said, its performance in this setting is still enough for the vast majority of bedrooms or home offices.
The Dreo Air Purifier 539S is very quiet. It's almost inaudible at its lowest Sleep fan speed setting, which is ideal for overnight use in smaller bedrooms or nurseries. Meanwhile, while its fan noise can be disruptive if it's set up nearby, it still shouldn't be much of a distraction if you're running it in a larger space and have a bit of distance between you and it.