The Dreo Air Purifier 338S is a mid-range smart air purifier intended for bedrooms, offices, and other small to medium-sized spaces. It uses a three-stage filtration system with a pre-filter, HEPA filter, and an activated carbon layer, and includes an air quality sensor that automatically adjusts fan speed. It also supports smartphone app control, air-quality monitoring, scheduling, and adjustable ambient lighting, as well as an aroma pad compartment for essential oils.
Our Verdict
The Dreo Air Purifier 338S is a decent option for households with pets. It can help reduce airborne particles from pet dander and fine dust stirred up by litter boxes, bedding, and everyday activities around the home. Its quiet operation also makes it practical to leave running for long stretches near a cat bed or dog crate, without adding much background noise. That said, its CADR is not the fastest, so it will take some time to noticeably reduce higher concentrations of pet-related allergens, such as after brushing, vacuuming, or cleaning a litter box.
Quiet enough to run around pets continuously.
Display and ambient lighting turn completely off.
Less effective when operated at quieter speeds.
The Dreo 338S is a great fit for the bedroom. It handles particle filtration well enough for all but the largest bedrooms, reducing airborne dust, pollen, and other allergens while you sleep. It's also impressively quiet, so running it beside your bed overnight won't leave you tossing and turning over background noise. You can tweak settings from the smartphone app without ever leaving your pillow, and both the display and ambient lighting dim down if you'd rather sleep in the dark. There's even a compartment for aroma pads, so you can add a few drops of essential oil and wind down to something a little more calming.
Exceptionally quiet for overnight bedroom use.
Display and ambient lighting turn completely off.
Companion app allows adjustments without getting up.
Aroma pad compartment for your essential oils.
Small footprint takes up little floor space.
Less effective when operated at quieter speeds.
The Dreo AP338S's clean air delivery rate (CADR) is adequate, making it suitable for medium-sized rooms like bedrooms, home offices, and smaller living rooms, though it takes longer to clear the air in larger spaces.
CADR matches Dreo's advertised performance.
Adequate airflow for most medium-sized rooms.
Takes longer to clean larger spaces.
Less effective when operated at quieter speeds.
The Dreo 338S relatively small footprint, so it doesn't require much open floor space. Its tall, narrow shape makes it easy to place beside a bed, next to a desk, or in the corner of a room without getting in the way. That said, you'll still want to leave some clearance around it so air can circulate freely.
Small footprint takes up little floor space.
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Differences Between Sizes And Variants
The Dreo Air Purifier 338S is available in two colors: Black and White. We bought and tested a unit in White, though we fully expect the other version to perform identically. For those interested, here's the product label for our test unit.
If you come across another variant of this air purifier, let us know in the comments so that we can update our review.
Popular Air Purifier Comparisons
The Dreo 338S is a compact mid-range air purifier that emphasizes quiet operation and smart features over raw cleaning power. Within Dreo's lineup, it sits below the Dreo Air Purifier 539S, trading some cleaning power for a smaller footprint and quieter operation. This model is also less powerful than the Blueair Blue Pure 511i Max, which delivers substantially stronger particle filtration despite being similarly compact. It's more closely matched with the Levoit Core 300S, though the Levoit has a slightly higher cleaning rate and is quieter on higher settings. Unlike simpler competitors like the PuroAir 240, this model also has smartphone connectivity for remote control, monitoring, and scheduling.
If you're interested in alternatives, check out our recommendations for the best air purifiers, the best small air purifiers, and the best air purifiers for bedrooms.
The Dreo AP338S is a better air purifier than the Levoit Core 200S. Both are compact models with companion apps, but the Dreo delivers a higher particle filtration rate, allowing it to clean somewhat larger rooms. It also runs more quietly at its lowest fan speeds and does a slightly better job of cleaning the air at those settings. On top of that, the Dreo has a built-in air quality sensor with automatic fan speed adjustment, which the Levoit lacks, though the Core 200S does have the edge in size, coming in slightly smaller.
The Dreo AP338S and Levoit Core 300S are closely matched compact smart air purifiers. The Levoit has a somewhat higher clean air delivery rate and can effectively handle a slightly larger room, while the Dreo runs a little quieter. Both offer companion apps, automatic air quality monitoring, timers, and displays that can be turned off for bedroom use. The Dreo distinguishes itself with adjustable ambient lighting and an aroma pad compartment, while the Levoit offers a broader selection of specialty replacement filters designed for needs like smoke, toxins, and pet allergens.
The Blueair Blue Pure 511i Max is the better air purifier compared to the Dreo AP338S. Despite similarly compact dimensions and both meant for small to medium spaces, it has a much higher clean air delivery rate, giving it substantially stronger particle filtration and the ability to clean a larger space in the same amount of time. Both are exceptionally quiet and offer companion apps with automatic air quality monitoring, though the Dreo adds adjustable ambient lighting and an aroma pad compartment for essential oils.
The Dreo AP338S is a better air purifier than the PuroAir 240. They're similarly compact, and both operate quietly, but the Dreo has a higher clean air delivery rate, allowing it to clean larger spaces more effectively. It also offers Wi-Fi connectivity and a companion app for remote control, scheduling, and air quality monitoring, while the PuroAir has no app or remote. Both can automatically adjust fan speed based on air quality, but the Dreo offers stronger overall performance and more convenience features.
Test Results
This air purifier also has an aroma pad compartment where you can add replaceable Aroma Pads infused with essential oils for fragrance.
The controls are comprehensive and easy to access from the front of the unit. You can choose between Sleep mode and four standard fan speeds, plus an Auto mode that adjusts the fan speed based on the air quality sensor. A more powerful Turbo mode is available through the app.
One of the more unique features is the large vertical air-quality display on the front, which makes the current air-quality status easy to check at a glance from across the room. The app lets you monitor air quality in greater detail and provides granular controls for the ambient lighting on the front of the unit, as shown in this video. The display can be dimmed for nighttime use, and there's also a timer and filter change indicator. There's no physical remote, but you can control the purifier remotely through the Dreo smartphone companion app.
The Dreo Air Purifier 338S uses a three-stage filtration system consisting of a pre-filter, HEPA filter, and activated carbon pellets. The pre-filter captures larger debris like hair, lint, and dust, while the HEPA filter targets finer particles like pollen, smoke, and fine dust. The activated carbon layer is intended to help reduce odors and gases like cooking smells, smoke, formaldehyde, and other VOCs, though the relatively small amount of carbon used is unlikely to make a meaningful dent in VOC levels, as explained in our air purifier R&D article. Its HEPA filter has also been independently tested and certified, though the specific testing standard isn't stated. Replacement filters are available directly from Dreo once the original reaches the end of its usable life.
On its Turbo setting, this air purifier delivers alright air cleaning performance that's best suited to medium-sized rooms like bedrooms, home offices, and smaller living rooms. Its measured clean air delivery rate of 115 CFM (cubic feet per minute) also matches Dreo's advertised rating, so its real-world airflow lines up with the manufacturer's claims.
Particle filtration is middling when you want to keep noise to a minimum. At a reasonably quiet fan speed, it moves enough clean air for a small bedroom or similarly sized space, but it takes some time to noticeably reduce airborne particles. Increasing the fan speed improves filtration speed, though it also makes the unit more audible.
This is a very quiet air purifier. At its lowest fan speed, it produces very little noise, making it a great option for running overnight or while you're working. It remains reasonably quiet at its highest setting, too, so you can run it more aggressively when you need faster air cleaning without creating too much disruption.