Compare Humidifier
Dyson Purifier Humidify+Cool Formaldehyde PH04 scores higher on safety - here's why.
R3 scored the Dyson Purifier Humidify+Cool Formaldehyde PH04 7.8/10 and the Stadler Form HERA Ultrasonic Humidifier 6.5/10 on the same humidifier scoring system, weighing safety, efficacy, and usability. The Dyson Purifier Humidify+Cool Formaldehyde PH04 comes out ahead, led by its safety score (7.8/10 vs 6.1/10).
The most important dimensions, side by side.
See which one actually scores higher — and why
Free account unlocks full safety scores, spec-by-spec breakdown, and the R3 verdict on Dyson Purifier Humidify+Cool Formaldehyde PH04 vs Stadler Form HERA Ultrasonic Humidifier.
Unlock the full Dyson Purifier Humidify+Cool Formaldehyde PH04 vs Stadler Form HERA Ultrasonic Humidifier breakdown
Free account unlocks all safety scores, complete spec comparison, scoring rationale, and the R3 verdict on which one to buy.
Everything you need to make the call - who each one is for, and who should skip it.
Go for it if you...
You want the gold standard in clean humidification: evaporative technology, UV-C sterilization, and an auto-humidistat in one device.
You also need a full air purifier with HEPA H13 filtration and formaldehyde destruction for your living space.
You run it in an open-plan or large room during the day, not in a bedroom or nursery overnight.
The $1000 price is within your budget and you want everything handled by one device.
You are comfortable with hand-washing and a monthly citric acid descale routine.
You live in a warm or very dry climate where evaporative humidifiers underperform and ultrasonic is your only real option.
You want the best ultrasonic humidifier available and are committed to using distilled or demineralized water.
Coverage and output are paramount — you need one unit to humidify a large open-plan space or multiple connected rooms.
You can find it new or refurbished from a reputable authorized retailer and are comfortable with its discontinued status.
Quiet operation (32 dB) matters for nursery or bedroom use.
The main thing to know
The Dyson PH04 is the most feature-complete air quality device in this category — evaporative humidification, UV-C water sterilization, humidistat, HEPA H13 air purification, and formaldehyde destruction all in one machine. The tradeoffs are real: 62.4 dB makes it unsuitable for sleep environments, the tank is unspecified plastic with no BPA-free confirmation, and the $999 price is in a category of its own.
The HERA is the most capable ultrasonic humidifier scored — maximum output, maximum coverage, quiet, included demin cartridge, built-in humidistat. But it is discontinued (not available new from Amazon or the brand site), and its ultrasonic mechanism carries documented PM2.5 risks that the demineralization cartridge cannot fully resolve. R3 ranks it #6 of 7 for that reason.
Skip this if you...
You need a quiet humidifier for a nursery or bedroom — 62.4 dB will disrupt sleep.
The unspecified plastic tank (no BPA-free confirmation from Dyson) is a dealbreaker for your family.
You are looking for strong price-to-value — this is a luxury purchase.
You have infants, toddlers, or family members with asthma or respiratory sensitivities — ultrasonic aerosol risk is not acceptable.
You want to buy from Amazon or the brand's primary website — this product is discontinued and not readily available.
You use tap water and won't regularly replace the demineralization cartridge — white dust and mineral aerosol buildup are real hazards.
Neither of these quite what you're looking for?
I've reviewed all Humidifier options at every price pointEvery Humidifier in our database is scored using R3's deterministic scoring system - the same inputs always produce the same score. For this comparison, we evaluated Dyson and Stadler Form across 3 independent criteria: Safety (89%), Efficacy (8%), Usability (3%). No sponsored rankings. No paid placements.
Straight answers - no sponsored content, no filler.
I'd start with Dyson Dyson Purifier Humidify+Cool Formaldehyde PH04 - it scored 7.8/10 overall in our scoring system. Safety is our top-weighted scoring pillar, followed by efficacy, and usability. Check which pillar matters most to your family and compare those specific scores.
R3 uses a deterministic scoring system - the same inputs always produce the same score. We evaluate each Humidifier across Safety, Efficacy, Usability using independently verified data. No sponsored rankings. No paid placements. Every score is fully reproducible.
Not necessarily. The overall score reflects how we weight those three pillars, but your priorities may differ. If you care most about safety, compare the safety scores directly. If budget drives your decision, the prices tell a clearer story. The "right" pick is the one that matches what matters most to your family.
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