How long does the 550 ml tank last?

At typical intermittent mist settings a tank this size runs for several hours before a refill; continuous mist drains it faster. The waterless auto-off shuts it down when the tank empties.

Can I use it without the light?

Yes. The 7-color LED is separate from the mist, so you can run the diffuser in the dark or leave the light on as a night light.

Does it need distilled water?

Distilled or filtered water is recommended. Tap water leaves mineral scale that clogs the ultrasonic plate and shortens the unit's life.

How much floor space does it cover?

A 550 ml ultrasonic diffuser scents a bedroom or medium room well. In a large open-plan space the scent will be faint compared with a reed diffuser or a stronger commercial unit.

Can it run from a power bank?

It is USB powered, so a power bank or laptop USB port can run it. Check the adapter's output, since a weak port gives a thinner mist.

What comes in the box?

Typically the diffuser unit, a USB cable and a short manual. Essential oils are not included.

What do buyers say about the Kayannuo Aromatherapy Essential Oil Diffuser?

Rated 3.4 out of 5 from 8 ratings.

Where can I buy the Kayannuo Aromatherapy Essential Oil Diffuser?

2 stores we checked sell it, including Walmart, Amazon.

Kayannuo Aromatherapy Essential Oil Diffuser

Best price now

$6.99at WalmartChecked 5 h ago

Compared across 2 stores. Prices are checked against each store and labelled with when.

Visit Walmart

Kayannuo Aromatherapy Essential Oil Diffuser

Best price now

$6.99at WalmartChecked 5 h ago

Compared across 2 stores. Prices are checked against each store and labelled with when.

Visit Walmart

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Price facts

Lowest price today: $6.99 at Walmart (checked Nov 15, 2026).
Checked at 2 stores.

Our take on the Kayannuo Aromatherapy Essential Oil Diffuser

The Kayannuo is a 550 ml ultrasonic diffuser that doubles as a cool-mist humidifier for a bedroom or living room. It runs on USB power and adds a timer, waterless auto-off and a 7-color LED night light. The large tank means fewer refills than the small 100–300 ml diffusers it competes with, but USB power limits output compared with mains-powered rivals. Owners of this class of diffuser value the auto-off safety and the light; mist volume and plastic build are the usual weak points.

Best forBedrooms and small living roomsBuyers who want a night light and diffuser in oneAnyone who wants a large tank and fewer refillsGifting

Pros

550 ml tank holds more than most budget diffusers
Timer plus waterless auto-off for safe unattended use
7-color LED light works as a night light
Cool mist adds moisture as well as scent
USB powered, so it can run from a power bank or laptop

Cons

USB power gives weaker mist than mains-powered units
Plastic body feels less premium than ceramic or wood rivals
No app or smart-home control
Light colors cycle rather than hold a single setting on many units

Kayannuo Aromatherapy Essential Oil Diffuser prices at every store

WalmartNew
In stockSold by RUIYANQI CO.,LTDReturns: Sold by a Walmart Marketplace seller; returns go to the seller under the seller's returns policy.
$6.99+ $2.98 shippingChecked 5 h ago
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AmazonNew
Availability unknown
As an Amazon Associate, Deal.ai earns from qualifying purchases.
$29.99Checked 5 h ago
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Kayannuo Aromatherapy Essential Oil Diffuser price history

Lowest price we've seen: $29.99 on Nov 15 at Amazon. Tracked across 1 store since Nov 15.

About the Kayannuo Aromatherapy Essential Oil Diffuser

This is an ultrasonic aromatherapy essential oil diffuser with a 550 ml water tank. It works as a cool mist humidifier and is intended for large rooms in the home.

It has a timer and shuts off automatically when the water runs out. Its LED light cycles through 7 colors.

Type: Ultrasonic essential oil diffuser and cool mist humidifier
Capacity: 550 ml
Lighting: 7-color LED lights
Features: Timer, waterless auto-off
Color: Yellow

Specifications

color: YellowSource
actual_color: YellowSource

Questions and answers

How long does the 550 ml tank last?: At typical intermittent mist settings a tank this size runs for several hours before a refill; continuous mist drains it faster. The waterless auto-off shuts it down when the tank empties.
Can I use it without the light?: Yes. The 7-color LED is separate from the mist, so you can run the diffuser in the dark or leave the light on as a night light.
Does it need distilled water?: Distilled or filtered water is recommended. Tap water leaves mineral scale that clogs the ultrasonic plate and shortens the unit's life.
How much floor space does it cover?: A 550 ml ultrasonic diffuser scents a bedroom or medium room well. In a large open-plan space the scent will be faint compared with a reed diffuser or a stronger commercial unit.
Can it run from a power bank?: It is USB powered, so a power bank or laptop USB port can run it. Check the adapter's output, since a weak port gives a thinner mist.
What comes in the box?: Typically the diffuser unit, a USB cable and a short manual. Essential oils are not included.
Where is the Kayannuo Aromatherapy Essential Oil Diffuser cheapest?: At Walmart, for $6.99, as of our latest check.
What do buyers say about the Kayannuo Aromatherapy Essential Oil Diffuser?: Rated 3.4 out of 5 from 8 ratings.
Where can I buy the Kayannuo Aromatherapy Essential Oil Diffuser?: 2 stores we checked sell it, including Walmart, Amazon.