Dreo Air Purifier 338S: Specs, Features, Pros & Cons
This review measures the Dreo Air Purifier 338S against the full 22-spec sheet we track for Air Purifiers, comparing it like for like with the 31 other models in our database. It earns a VS Score of 52 out of 100 — the weighted result of every verified specification measured against the class average.
On the spec sheet it is strongest in filtration and weakest in performance. Its clearest single advantage over the class average: a lower min noise level — 18 dB vs 22.26 dB (avg). None of our retail partners currently lists the Dreo Air Purifier 338S, so availability may be limited; a missing price never affects the VS Score. A transparency note: this spec sheet is 64% complete. Anything unverified shows as Unknown and is left out of the score — we never estimate a missing value.
Category strengths
Where the Dreo Air Purifier 338S beats the average
- Has true HEPA filter ?
- A lower min noise level ?18 dB vs 22.26 dB (avg)
- Has app control ?
- Has air quality sensor ?
- Has voice assistant ?
- Has auto mode ?
- Has activated carbon filter ?
- Has timer ?
- Has sleep mode ?
- Has filter replacement indicator ?
Where the Dreo Air Purifier 338S trails the average
- A much lower coverage area ?178 sq ft vs 333.52 sq ft (avg)
- A much lower CADR (smoke) ?115 CFM vs 212.72 CFM (avg)
- Fewer filtration stages ?3 vs 3.56 (avg)
Editor’s note
The 338S is Dreo's entry smart purifier: the same compact 360-degree cylinder as the non-smart 338, with Wi-Fi, an app and voice-assistant control added. Everything that matters about how it cleans a room is shared with the cheaper model, so the decision is really whether you want to schedule it, check air quality from your phone, or say a sentence to turn it on. If you will use those things daily, the S is worth it; if you would set it to auto and forget it, the plain 338 does the same job.
The numbers are small-room numbers, and Dreo's marketing makes them look bigger than they are. Dreo quotes 115 CFM, which it labels a CADR, and a headline coverage of 856 square feet. That area is a one-air-change-per-hour figure; at the 4.8 changes per hour the industry uses for a proper clean, the same unit covers about 178 square feet, which is a bedroom or a home office, not an open-plan living space. Dreo publishes no separate smoke, dust and pollen ratings, so I have recorded its single figure and said so in the notes.
What it does well is be quiet and simple. The minimum noise level is 18 dB, which is close to inaudible in sleep mode, and there are six fan speeds, four airflow modes, a 12-hour timer, a real-time air-quality sensor driving an auto mode, and a filter-change reminder. The filter is a three-stage unit with an aroma pad slot, which is a gimmick but a harmless one. Dreo does not publish power draw, filter life in months, weight or the maximum noise level, so those fields are empty rather than guessed.
Buy it for a bedroom, nursery or office where quiet matters and you want app control. Do not buy it for a large room on the strength of the 856 square foot claim.
Specifications
Quality bars are generated automatically against 31 other air purifiers.
Performance
Clean Air Delivery Rate — how quickly smoke particles are scrubbed from the air.
The room size the purifier is rated to clean effectively.
How many times the air in the rated room is cycled each hour.
The number of filtration layers air passes through.
Filtration
A certified HEPA filter captures 99.97% of 0.3-micron particles.
The HEPA grade of the main filter (e.g. H13).
A carbon layer absorbs odours, smoke and VOCs.
Pellet-based carbon beds absorb more odour than thin coated sheets.
A rinseable pre-filter catches hair and large dust to extend filter life.
How long the main filter lasts before replacement.
Noise & power
The lowest-speed noise output; quieter suits bedrooms.
Noise at full speed; lower is better.
Maximum power draw; lower costs less to run continuously.
A dimmed, near-silent mode for overnight use.
Design
A lighter unit is easier to move between rooms.
The height of the unit.
Smart features
Measures particle levels to show and react to air quality.
Adjusts fan speed automatically based on measured air quality.
Control and monitor it from a phone app.
Works with Alexa and Google Assistant.
Tells you when the filter needs replacing.
Schedule the purifier to switch off automatically.
How the VS Score works — and what it can’t tell you
Every measurable spec is scored against the average of all the Air Purifiers we track: matching the class average scores 50, clearly beating it climbs towards 100, and each spec counts according to an editorial weight that reflects real-world impact — a battery-capacity gap moves the score far more than a colour-options list. The quality bars on the spec cards above show where this model sits inside the full range for its class, and the overall VS Score rolls every weighted result into one number.
Unknown values are never estimated. A spec this product doesn’t report simply drops out of its scoring — it isn’t penalised with a guess — but a thinner spec sheet does mean a score built on fewer data points, which is why completeness is disclosed under About this data.
Most importantly: a spec-sheet lead is not the same as a better product. Megapixels, gigahertz and benchmark points describe capacity, not experience — image processing, software optimisation, thermals, haptics and ergonomics decide how a device actually feels, and no table captures reliability or long-term support quality. Treat the VS Score as a structured summary of what can be measured, not a substitute for your own priorities.
About this data
- Specifications are compiled from each manufacturer’s official spec sheet, cross-checked against trusted specification databases, and normalised into one schema so identical things are compared identically.
- Specifications last verified August 23, 2026.
- Data completeness: 14 of the 22 specs in this category are verified (64%). Anything we could not verify is shown as Unknown — never estimated — and is excluded from the score.
- Prices and availability come from live retailer feeds via our shopping partners and refresh throughout the day; a missing price means no partner currently lists the product, not that it is discontinued.
- Want the full picture? Our editorial guidelines explain how we research products, weight the scores and stay independent.
- Spotted an error in a spec? Tell us and we will correct the sheet.
Air Purifiers with similar specs to the Dreo Air Purifier 338S
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The bottom line
The Dreo Air Purifier 338S earns a VS Score of 52, a solid mid-pack result among the 32 air purifiers we compare here.
- Who it’s for
- Bedrooms, nurseries and home offices where an 18 dB floor and app scheduling matter, for buyers who will actually use the smart features.
- Who should look elsewhere
- Large or open-plan rooms – at a proper 4.8 air changes per hour it covers roughly 178 sq ft, not the 856 on the box. Also not for anyone who wants AHAM-verified smoke/dust/pollen ratings; Dreo does not publish them.
- The trade-off that matters
- Quiet, compact and genuinely smart against modest real-world coverage, a single unverified airflow figure in place of proper CADR ratings, and several specs Dreo simply does not publish.
- The main alternative
- Dreo Air Purifier 338 – the identical purifier without Wi-Fi, app or voice control, for anyone who would set auto mode once and never touch it again; it is the cheaper way to get the same clean air.
The VS Score is generated automatically from the weighted specifications above, measured against all other air purifiers in our database. Treat it as a shortlisting guide — not a substitute for your own priorities.
