Honeywell HCM-350: problems, parts and running costs
Checked: 2026-10-18
Summary
An evaporative wicking humidifier that adds invisible moisture to a bedroom without the white dust of ultrasonic models, best for a quiet sleeper who will keep up with filter changes. The recurring issues are fan noise on medium and high, a wick that molds if stored wet and needs replacing every 30-60 days, and the absence of a humidistat, auto shut-off and empty-tank alert. Wicks cost $16.95 each, so budget for that every 30-60 days, and the unit is a good buy at $60 or less but hard to defend above $100.
Common problems and fixes
- Fan noise on medium and high — TechGearLab calls it the noisiest model in its lineup with an annoying clicking noise on the highest setting, BabyGearLab scored Noise 2.0/10, and a six-month test measured 45 dB on high. Run it on low, where it is quiet. [3][8][10]
- Output ceiling next to ultrasonic models — BabyGearLab measured output at one hour at about two-thirds of the ultrasonic competition and scored Effectiveness 3.0/10. It cannot match an ultrasonic unit’s output. [8]
- No humidistat, auto shut-off or empty-tank indicator — Consumer Reports lists all three as absent, so the unit keeps running dry and monitoring is manual. [7]
- Saturated wick is hard to seat — BabyGearLab had difficulty fitting the casing over a fully saturated wick, and the unit will not work properly if the filter is squished. [8]
- Large footprint and intake clearance — it had the largest footprint in BabyGearLab’s test and needs open space around the intake vents. [8]
- Discontinued at Honeywell’s own store — the HCM-350 and HCM-350B are marked discontinued, which affects official support and warranty handling for leftover stock. [1]
Parts and consumables
- Replacement Filter A (HAC504) — $16.95 each at Honeywell; Honeywell says replace every 30-60 days, and a six-month test landed on 55-65 days at 11 gpg hard water and 45 days under heavy all-day use. [9][10]
- Protec antimicrobial cartridge — $13.95 for a two-pack; Honeywell suggests replacing it every 30 days. [9]
Yearly running cost
A new wick every 30-60 days at $16.95 each is the main cost, plus an optional Protec cartridge at $13.95 for a two-pack. TechGearLab estimated a lifetime cost of $203 and called the operating cost the bane of this model, driven by recurring wick replacements. Electricity is light: one tester measured 0.02 kWh per hour. No single annual figure is given in the sources.
When it is a good buy
Honeywell’s store showed $79.95 while the model was still listed; BabyGearLab and Consumer Reports listed it around $70 in 2018, Popular Mechanics saw roughly $70-76 in 2020, and TechGearLab used a $100 list price in its 2022 update. At $60 or less it is strong value for a basic evaporative humidifier with best-in-test cleaning and a 3-year warranty; from $60 to $80 it is fair and you should compare quieter ultrasonic units at the same price; from $80 to $100 it gets weak given the discontinued status, noise and wick cost; above $100 it is not defensible. Alternatives: quieter ultrasonic models such as the Levoit Classic 300S and Levoit Classic 200/LV600HH compare well at the same price, and Honeywell’s own newer top-fill evaporative models (HEV615/HEV620) are the better choice if you want a current, supported design.