Quick verdict
Buy the 338S only on a solid discount, for a small bedroom, nursery or desk corner under about 180 sq ft where its smaller size and quieter running matter. At or near list price, the Dreo 539S or the Levoit Core 300S gets you noticeably more cleaning for the same money.
Ideal for
- Small bedrooms, nurseries and offices up to ~180 sq ft (e.g. a 12x14 room)
- Shoppers who want a numeric PM2.5 readout and Wi-Fi in a small footprint
- Light sleepers who prefer a smaller, quieter unit over raw airflow
Not ideal for
- Rooms over ~180 sq ft (the Dreo 539S covers ~245 sq ft for about $10 more)
- Smoke or strong-odor problems
- Buyers who want verified filter cost before they buy
The full picture
The Dreo Air Purifier 338S (DR-HAP008S) is a compact smart purifier with an AHAM Verifide 115 CFM CADR, a 3-in-1 filter (pre-filter, HEPA, activated carbon), a PM2.5 sensor with an AQI display, Wi-Fi with Alexa, app-based filter-life tracking and a built-in aroma pad for essential oils. RTINGS found it quieter than the larger Dreo 539S, which is its main advantage. At a $99.99 list price, though, it sits only $10 below the 539S, which delivers 37% more CADR.
Dreo 338S at a glance
- CADR — smoke (CFM)
- 115
- Coverage (sq ft)
- 178
- Coverage detail
- 4.8 ACH (178 sq ft); Dreo's 856 sq ft claim is 1 ACH
- Filtration
- 3-in-1 filter: pre-filter + HEPA + activated carbon
- HEPA filter
- HEPA (grade not published)
- Noise — low (dBA)
- 18
- Auto mode
- Yes
- Air quality sensor
- Yes
- Smart app / Wi-Fi
- Yes
- Room size
- Small
- Notable feature
- PM2.5/AQI display plus a built-in aroma pad for essential oils
Source: CADR, certifications, noise and feature list from Dreo's 338S store page and Amazon DR-HAP008S listings; comparative noise and control notes from RTINGS's 338S review and its 338S vs 539S comparison (checked 2026-10-01). Filter price and life were not verified. Research-based; not hands-on tested.
This is a research-based review — our analysis draws on manufacturer specifications, manuals, warranty terms, and verified owner feedback rather than our own hands-on testing, and we note where a detail couldn't be confirmed. How we review
The in-depth review
The Dreo 338S is a capable purifier for a small bedroom or nursery of up to about 180 square feet, with a verified CADR, a PM2.5 readout, Wi-Fi and quieter running than its bigger sibling. The problem is the price ladder. At $99.99 list, it costs only $10 less than the Dreo 539S, which moves 37% more air. Buy the 338S on a real discount or for a genuinely small room; otherwise step up.
Which Dreo is this?
The 338S is model DR-HAP008S, the Wi-Fi version of the Dreo 338 (DR-HAP008). Both carry the same AHAM Verifide rating, the same PM2.5 sensor and the same built-in aroma pad. The "S" adds the Dreo app, Alexa voice control and app-based filter-life tracking. It sits below the 539S in Dreo's lineup and is the smaller of the two machines.
How much room does it really clean?
The 338S has an AHAM Verifide CADR of 115 CFM. Using the 4.8 air-changes-per-hour standard, that covers about 178 square feet, roughly a 12x14 bedroom. In a 10x12 nursery it reaches about 7 air changes an hour on its top speed, so it can sit on a low setting overnight and still keep up.
Dreo advertises 856 square feet. That is one air change per hour: a slow background refresh, not allergy-season or smoke-day performance. Put a 338S in a 300-square-foot living room and it manages under 3 changes an hour at full speed. Our room size calculator will show you whether your room is in range.
The numbers that matter for the buying decision sit side by side:
| Dreo 338S | Dreo 539S | Levoit Core 300S | |
|---|---|---|---|
| AHAM CADR | 115 CFM | 158 CFM | 141 CFM |
| Room at 4.8 ACH | ~178 sq ft | ~245 sq ft | ~219 sq ft |
| List price | $99.99 | $109.99 | ~$100 |
Noise and bedroom use
Dreo quotes 18 dB in Sleep mode and does not publish a top-speed figure. RTINGS compared the 338S directly with the 539S and found the 338S runs more quietly and is easier to place in a bedroom or office. That is the clearest reason to choose it: if the purifier sits three feet from your pillow and the room is small, a lower fan pitch can matter more than extra CFM.
Both Dreo models have adjustable ambient lighting. RTINGS also notes that on both, Turbo is reachable only from the app, not from the buttons on the unit. In a child's room that is arguably a feature. Small hands cannot crank it to full blast.
Smart features and the aroma pad
The PM2.5 readout is the most useful feature here. It turns "is the air bad right now?" into a number, and Auto mode uses the same sensor to ramp the fan when you cook or light a candle. The app adds remote control, Alexa and filter-life tracking, so you get a reminder before the filter is clogged rather than a guess.
The aroma pad is a small tray for a few drops of essential oil. It is the rare purifier feature that adds something to the air rather than taking it out. It is not a reason to choose this model, and anyone buying for asthma or a baby may prefer to leave it dry.
Filters and running cost
The 338S uses a 3-in-1 filter: pre-filter, HEPA and an activated-carbon layer. The current price and rated life of the 338-series replacement filter could not be confirmed for this review. Check both before you buy, because on a $70 to $100 purifier the filter is the main long-term cost.
Electricity is also unpublished. Dreo does not list wattage for the 338S. The running cost calculator can estimate it once you see the wattage on the unit's label.
What to watch for
The 338S is new, with few owner reviews so far, so there is no reliable pattern yet on sensor drift, fan noise over time or app reliability. Dreo's published spec sheet is thinner than those of Levoit, Winix or Coway. It gives no dust or pollen CADR, no wattage and no top-speed noise. The AHAM verification is the one number you can lean on, and it is a modest one.
Is it the right one for you?
Buy the Dreo 338S if your room is under about 180 square feet, quiet running matters more than speed, and you find it well below the price of the Dreo 539S. That gap needs to be $25 or more to make sense. A dorm room, nursery or desk corner is its natural home. Our best air purifiers for dorm rooms list covers other small-room options.
Skip it if the price gap to the 539S is small. The 539S handles a full 12x18 bedroom and was measured by RTINGS as faster than the Levoit Core 300S. If you would rather have a model with years of owner feedback and a display that goes fully dark, the Levoit Core 300S is the safer small-room pick at a similar price. For anything bigger than a bedroom, look at the Winix 5530.
Performance breakdown
Research-based editorial judgments from specs, warranty terms, and verified owner feedback — not lab measurements. How we score
Pros and cons
What works
- AHAM Verifide 115 CFM CADR, so the small-room rating is trustworthy
- Numeric PM2.5 / AQI display, Auto mode, Wi-Fi app and Alexa
- RTINGS found it quieter than the Dreo 539S
- App tracks filter life
- Dreo lists 18 dB in Sleep mode
What doesn't
- At $99.99 list it costs only $10 less than the 539S, which has 37% more CADR
- Turbo mode is app-only, per RTINGS
- Dreo does not publish wattage, top-speed noise or a dust/pollen CADR split
- New model with few owner reviews so far
Best alternatives to Dreo 338S
Shark
Shark BreatheClear MAX
Best hands-off sensor purifier
Shark's 2026 HP362 adds motion, light and VOC sensing and a 6-year filter claim to a ~220 CFM tower. Realistic fit: rooms up to ~340 sq ft.
- 220 CFM CADR
- 341 sq ft
- $360–$450 ($449.99 list)
Shark
Shark NeverChange Air Purifier MAX
Best for skipping yearly filter changes
Shark's HP302 trades yearly filter buys for one long-life filter. Energy Star lists 204 CFM smoke CADR, so size it for ~316 sq ft, not 1,400.
- 204 CFM CADR
- 316 sq ft
- $240–$400 ($399.99 list; often $280–$300 on sale)
Blueair
Blueair Blue Pure 511i Max
Best smart Blueair for small bedrooms
Blueair's smallest smart Blue Pure: about 237 sq ft of coverage on 17 W, with a $29.99 filter and a polished app. A close rival to the Levoit Core 300S.
- 153 CFM CADR
- 237 sq ft
- $95–$140 ($139.99 list)
Dreo
Dreo 539S
Best smart bedroom pick under $110
Dreo's Wi-Fi 539S posts an AHAM Verifide 158 CFM CADR and a live PM2.5 readout for about $75–$110. Right-sized for bedrooms up to ~245 sq ft.
- 158 CFM CADR
- 245 sq ft
- $75–$110
Frequently asked questions
Dreo 338S or 539S: which should I buy?
For most rooms, the 539S. It has a 158 CFM CADR against the 338S's 115 CFM, covering about 245 sq ft instead of 178, for about $10 more at list. Pick the 338S only for a small room where its quieter running and smaller size matter, or when it is discounted well below the 539S.
How big a room can the Dreo 338S clean?
About 178 sq ft at 4.8 air changes per hour, based on its 115 CFM CADR. Dreo's 856 sq ft figure assumes one air change per hour.
What is the difference between the Dreo 338 and 338S?
The 338S (DR-HAP008S) adds Wi-Fi, app control and Alexa to the 338 (DR-HAP008). Both are listed with the same AHAM Verifide rating, PM2.5 sensor and aroma pad.
Can you put essential oils in the Dreo 338S?
Yes, on the built-in aroma pad Dreo designed for that purpose. Put oil only on that pad, never on the filter itself.