Compare Humidifier
Honeywell HCM-350 Cool Moisture Humidifier scores higher on safety - here's why.
R3 scored the Honeywell HCM-350 Cool Moisture Humidifier 7.9/10 and the Levoit Classic 300S Smart Ultrasonic Humidifier 5.7/10 on the same humidifier scoring system, weighing safety, efficacy, and usability. The Honeywell HCM-350 Cool Moisture Humidifier comes out ahead, led by its safety score (7.8/10 vs 5.7/10).
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 Honeywell HCM-350 Cool Moisture Humidifier vs Levoit Classic 300S Smart Ultrasonic Humidifier.
Unlock the full Honeywell HCM-350 Cool Moisture Humidifier vs Levoit Classic 300S Smart 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 safest humidifier type for a child's room — evaporative wicks physically trap minerals and microbes, not just filter them.
Easy cleaning is important to you — the tank and tray go in the dishwasher, which makes it genuinely possible to clean as often as the EPA recommends.
You're willing to use a $100 hygrometer alongside it to keep humidity in the safe 30–50% range.
You will use distilled or demineralized water exclusively — this removes the PM2.5 risk entirely.
App control and smart humidistat (VeSync app) are a priority for automating bedroom humidity.
Quiet operation matters most: 30 dB makes this the best-in-category option for infants and light sleepers.
Budget is a constraint and $80 is your ceiling for a large-room humidifier.
You want a large 6L tank that runs 8–12 hours overnight without refilling.
The main thing to know
The HCM-350 earns a strong safety score because evaporative technology eliminates the biggest humidifier risk — aerosolized minerals and bacteria. The one real gap: no humidistat means it will keep running past the EPA-recommended 50% RH ceiling unless you manually turn it off.
The Classic 300S scores lower than most mainstream reviews suggest because R3 weights air-quality risk above convenience features. Ultrasonic humidifiers with tap water generate measurable fine particulate matter indoors. If you use distilled water exclusively, that risk largely disappears — and the 300S delivers excellent app control, near-silent operation, and a large tank at the lowest price in the category.
Skip this if you...
You need a set-it-and-forget-it humidifier — without a humidistat, you must manually monitor and shut off the unit to avoid over-humidifying.
Filter replacement cost bothers you — evaporative wicks (HAC-504AW) typically need replacement every 1–2 months.
Your household uses tap water and you are not prepared to switch to distilled — the white dust and fine particulate risk is real.
You want to know exactly what material your water tank is made of before purchasing.
A child or family member has asthma, respiratory sensitivities, or you live in a hard-water area.
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 Honeywell and Levoit 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 Honeywell Honeywell HCM-350 Cool Moisture Humidifier - it scored 7.9/10 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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