Humidifiers

Blueair InvisibleMist H35i

#2 · Best Value
7.7 /10 Our score
Lowest verified price $149.99 Amazon
Our verdict
A smart, low-cost choice for a bedroom or medium room where the humidifier runs all winter. Expect modest humidity gains and audible fan noise, in exchange for easy cleaning and cheap running costs.

Pros

  • Lowest measured operating cost in TechGearLab's test
  • Dishwasher-safe, BPA-free tank
  • Top-fill design with smart controls
  • Inexpensive wicks every 6 months
  • Warranty extends to 3 years with registration

Cons

  • Plateaued near 51% RH in lab testing
  • Bob Vila's testers refilled it daily to hold about 45% RH
  • 49.6 dB constant fan noise
  • Blueair also sells an H35i G2, so check the model before buying

Disclosure: We may earn a commission when you purchase through links on this page. This does not affect our editorial rankings.

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Last reviewed October 31, 2026
Review

What to know about Blueair InvisibleMist H35i

A 3.5 L top-fill smart evaporative humidifier rated for 500 sq ft, with a dishwasher-safe, BPA-free tank. TechGearLab measured the lowest operating cost of the 14 units it tested (about $42/yr), and Bob Vila named it Best Smart. It plateaus near 51% RH.
Editorial notes

Why it stands out

Why we like it

TechGearLab measured the lowest annual operating cost of the 14 humidifiers it tested, about $42 a year, and named it Best Value for Constant Use. Bob Vila named it Best Smart and rated cleaning 5 out of 5.

Blueair lists a dishwasher-safe tank and a wick that is replaced every 6 months at a modest price. The warranty is 1 year, extending to 3 with registration.

What to know

Skip it if you need to push humidity high or want a silent bedroom unit. It plateaued near 51% RH in lab testing, and constant fan noise measured 49.6 dB.
Performance

Score breakdown

Hygiene & Ease of Cleaning

How easy it is to fully disassemble, reach and dry every wet surface. Covers dishwasher-safe or boilable parts, mold-inhibiting features, and parts count. Weighted heavily by BabyGearLab (35%) and stressed by Babylist, Forbes and RTINGS.

8.2
Dishwasher-safe tank (Blueair), cleaning rated 5/5 (Bob Vila), and an auto-dry button.
Humidifying Performance

Ability to raise and hold nursery humidity in the 40–50% range: tested output, coverage for the room size, overnight runtime per tank, and humidistat or auto-mode accuracy.

7.0
Plateaued near 51% RH and needed daily refills.
Quiet & Sleep-Friendly

Measured or rated noise, absence of gurgles and beeps, dimmable or switch-off lights, and nursery extras like a red night light or white noise that help rather than disturb sleep.

6.5
TechGearLab measured 49.6 dB. Sleep mode is very quiet (Bob Vila).
Health, Safety & Materials

Cool-mist or evaporative design (no burn risk), stainless or BPA-free water-contact materials, and white-dust/mineral mitigation such as demineralization filters or evaporative design. Also covers tip and leak resistance, auto shut-off, and any recalls or regulatory warnings.

8.0
Evaporative with a BPA-free tank. UV and antimicrobial measures are manufacturer claims.
Ease of Use

Filling (top-fill vs flip-tank), controls usable in the dark, app reliability, leak-free refills, and how easy it is to move or place.

8.0
Top-fill, app control and auto mode.
Value

Street price plus ongoing costs (filters, cartridges), weighed against warranty length and performance.

8.6
$149.99 with the lowest measured running cost and $19.99 six-month wicks.
Specifications

Blueair InvisibleMist H35i specs

Design

Humidifier type
Evaporative (pump-fed wick)

Health & materials

Water tank material
BPA-free plastic (Blueair)
Dishwasher-safe water-contact parts
Yes

Performance

Tank capacity
3.5 L
Max runtime per tank (manufacturer)
48 hours
Rated room coverage
500 sq ft
Built-in humidistat / auto mode
Yes
Mist temperature
Cool (invisible vapor)

Sleep

Noise (manufacturer-rated or lab-measured)
49.6 dB
Built-in night light
No
Built-in white-noise / sound machine
No

Ease of use

Top-fill tank
Yes

Running cost

Requires replaceable filter/cartridge
Yes

Features

Wi-Fi app / voice control
Yes

Health

White dust / mineral dispersal risk (per EPA type guidance)
Low – evaporative (EPA: not expected to disperse substantial minerals)
Antimicrobial / UV measures
UV-integrated pump; antimicrobial wick (manufacturer claims)

Ownership

Wick replacement interval / cost
Every 6 months; $19.99 (Blueair)
Warranty
1 years
Shopping

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Disclosure: We may earn a commission when you purchase through links on this page. This does not affect our editorial rankings.

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Lowest verified price $149.99
30-day low $149.99
90-day average $149.99
90-day low $149.99

Based on 2 retailer price observations captured during the last 90 days.

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