# CosmartAir BW406 Dehumidifier, 3,000 ml Tank

CosmartAir BW406 is a compact dehumidifier with a listed 3,000 ml tank, timer, sleep mode and colour lighting. The listing also claims up to 750 ml/day collection under specified conditions, automatic tank-full shut-off and a 640-square-foot coverage area, so check that the stated capacity suits the room and your expectations.

- [Original product page](https://bargainpostbox.co.uk/product/cosmartair-bw406-dehumidifier)
- [View offer](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- Market: UK
- Language: en-GB
- Currency: GBP
- Brand: CosmartAir
- Model: BW406
- Category: Home & Kitchen > Heating, Cooling & Air Quality > Humidifiers & Dehumidifiers
- Price: 56.99 GBP
- Previous price: 89.99 GBP
- Discount: 37%
- Price checked: 2026-11-13T05:59:15.840Z
- Rating: 4.9 / 5
- Reviews: 32

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## At a glance

- The listing claims a 3,000 ml transparent tank with automatic shut-off and an LED alarm when full.
- Timer settings are listed as 6, 8 or 12 hours, with sleep mode and seven independently controlled gradient lights.
- The screen is claimed to turn off after 10 seconds of inactivity. The listing also claims 30 decibels in sleep mode.

## Pros

- A transparent tank and claimed full-tank shut-off with an LED alarm make it easier to monitor collection and know when the tank needs attention.
- Timer choices and a screen-off feature offer practical control for bedroom use, where display light can be distracting.

## Specifications

### Identity
- Brand: CosmartAir
- Model: BW406
- Colour: Black
### Capacity and coverage
- Tank volume: 3000 Millilitres
- Claimed collection rate: up to 750 ml/day \(at 86°F and 80% RH\)
- Claimed floor area: 640 Square Feet
### Operation
- Power consumption: 40 watts
- Claimed 24-hour energy use: 0.96kWh
- Timer settings: 6, 8, or 12 hours
- Sleep-mode noise claim: 30 decibels
### Dimensions and materials
- Dimensions listed: 33D x 15W x 25H centimetres
- Material listed: Acrylonitrile Butadiene Styrene \(ABS\)

## Before you buy

- The listed 3,000 ml is the tank volume, while the separate collection claim is up to 750 ml/day at 86°F and 80% RH. The 640 Square Feet coverage claim is also not accompanied by operating conditions, so do not treat it as guaranteed room performance. The listing's 40-watt draw and 0.96kWh for 24-hour operation are arithmetically consistent, but real energy use and moisture removal will depend on conditions.

## In the box

- Power cord (Included)
- User manual (Included)

## A good fit for

- Buyers looking for a small-room dehumidifier with a transparent tank, timer and sleep-mode controls.
- People who want adjustable colour lighting and a screen claimed to switch off after inactivity.

## Less suited to

- Buyers who need independently verified performance for a large or persistently damp space.
- Anyone seeking a dehumidifier with a confirmed collection rate across a range of room conditions.

## Customer feedback

The supplied evidence contains aggregate ratings but no written customer feedback. The rating distribution is strongly positive, with a small three-star share, but it cannot show what customers liked or disliked. For buyers considering bedroom use, the listed sleep-mode and timer features are relevant claims, not proof of customer experience or measured performance.

## Frequently asked questions

### What is the tank capacity?
The listing gives a tank volume of 3000 Millilitres. It separately claims collection of up to 750 ml/day at 86°F and 80% RH.
### What timer settings are listed?
The listed timer options are 6, 8 or 12 hours, and the feature description says the timer can also be disabled.
### Does it switch off when the tank is full?
The listing claims automatic shut-off and an LED alarm when the tank is full.
### What is claimed about sleep mode?
The feature description claims operation as quietly as 30 decibels in sleep mode and says the screen turns off after 10 seconds of inactivity.

## Alternative options

- [Dehumidifier Electric 2 Modes, Dehumidifiers for Home 1800ml 500ml Daily \| 24-48H Timer, Quiet & Energy Efficient 22.5W Auto Defrost, Overflow Protection, LED Screen, for Bathrooms RV Closets Kitchen](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [SHINCO Mobile 30L/Day Smart Dehumidifier & Air Purifier with Activated Carbon Filter, 24 Hour Timer, Continuous Drain, Removes Excess Moisture in Large Houses](https://bargainpostbox.co.uk/visit/shinco-sdz1-30d-30l-day-dehumidifier)
- [Kresico 30L/Day Dehumidifier for Home & Basement up to 90m²/245m³, Quiet 40dB Electric Dehumidifier with Continuous Drain Hose, Dust Filter, 24H Timer,10 Y Warr](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [Devola 8L/Day Portable Compressor Dehumidifier for Home, Bedroom & Bathroom \| Prevent Mould, Damp & Condensation with this Compact Dehumidifier\! Energy Efficient, Timer, Child Lock & Quick Clothes Drying](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [Dehumidifier for Home 1800ML, High-Efficiency 400ML/Day Anti-moist \| Electric Dehumidifier Touch Control 4/8H Timer Auto Defrost & Shut-Off 7 Color Light Quiet for Bedroom Bathroom RV Basement](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [Dehumidifiers for Home, Dual-Core Dehumidifier, 1500ml/Day, 32dB Quiet \| 2.5L Water Tank, Auto Shut-Off, Timer, Up to 35 m², Portable Dehumidifier for Bedroom, Bathroom, Garage & Basement](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [Homtronics 2400ml Dehumidifier, Auto Shut Off, Timer & 10 Colour Light \| 2400ml water tank, 32dB quite, 8/12/24H timer, auto‑off energy saving dehumidifier for bedroom, office](https://bargainpostbox.co.uk/visit/homtronics-2400ml-dehumidifier-auto-shut-off-timer)
- [Dehumidifiers for Home, Up to 1500ml/day, 3.2L Water Tank, 35dB Quiet \| Auto Shut-Off, Timer & LED Touch Control, Auto Defrost, Portable Dehumidifier for Bedroom, Bathroom, Garage & Basement](https://bargainpostbox.co.uk/visit/vaplyn-dehumidifier-15l-day-32l-tank)
- [Devola 12L Dehumidifier, Low Energy Home Dehumidifier with Carbon Filter \| Costs 4.5p per hour to run, 2.9L Tank, Dual Filtration, Timer, Laundry Drying Mode with Fast Airflow, Continuous Drainage](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [Dehumidifier,35OZ（350sq ft）Small Dehumidifier for Home, Screen Display Quiet with Auto Shut Off,Dehumidifiers for Bedroom,Bathroom,Closet,RV](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [10L/Day Dehumidifier for Bedroom with Automatic Humidity Sensor & Display, 24-hour Timer, Laundry Drying, Continuous Drainage, Effective & Powerful Home Dehumidifiers \(10L Compressor Dehumidifier\)](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)
- [12L/Day Dehumidifier for Home, 32dB Quiet Dehumidifier with Dry Mode, 1.6L Tank, Digital Humidity Display, Energy-Efficient for Laundry Room, Closet & More](https://bargainpostbox.co.uk/visit/cosmartair-bw406-dehumidifier)

## Images

![CosmartAir BW406 Dehumidifier, 3,000 ml Tank — 1](https://bargainpostbox.co.uk/i/rwq8a-iXBv16rKDCnH2ErmEt75feVF5zLziytYklKEjBnxsQHV8Wq8ftRxfKBIh7ZPFNOIywOdaLDfCfdQ4vBqVT_4M9qaKbeVceXiwjmhttcvXKVA8P03hq.jpg)

![CosmartAir BW406 Dehumidifier, 3,000 ml Tank — 2](https://bargainpostbox.co.uk/i/RJRbQw4QhjhanP0Qbr4ZFxnsHQDh4TJ-vqc9DuX1Mapi-nx_wnWKzVx2tS-Hi7PrlcvXtaC7YydF4oJdY5u6A3HPfk3PWprrtRDFwxAq2niI613Rnbtoqlkj.jpg)

![CosmartAir BW406 Dehumidifier, 3,000 ml Tank — 3](https://bargainpostbox.co.uk/i/NjQAurAWDJ25NoKCkJ_V_4XKk-Rz3TLBlNKo4PQcta3xOeHCo5ZBuAFzym8sIWqUgxZyCDnX3Z7lOTvpg53aSqAFVwdMVIJ63LV7fUrhbtNg-TuKSdswPKAW.jpg)

![CosmartAir BW406 Dehumidifier, 3,000 ml Tank — 4](https://bargainpostbox.co.uk/i/SvHX_wS1qTriGX8wRbwOCW5AxsDT5IjJ8nAGeS0JgRumwRxRTtYiN1-wgCjv02b8zHWluKuU1bXbSjqVR-pNR6FJOcUI6bYHVsd3Dar4ci2S9-4O00uVrOvQ.jpg)

![CosmartAir BW406 Dehumidifier, 3,000 ml Tank — 5](https://bargainpostbox.co.uk/i/duf17lbOJDbt8Ec-l30XAewmefrVI6rPDUpvCYd6csOYsmA5V0WgWiSRxFaMVpRICYbEluoRvr8OAsz7cIo4BjDzXt7O_O0W9pNveUA9YOmBvxHQi7yvZpUT.jpg)

![CosmartAir BW406 Dehumidifier, 3,000 ml Tank — 6](https://bargainpostbox.co.uk/i/YZf35_FjqgEVtC44e0NlbqBJte8AwPNP2YxeUjgRpqZhZIvX_Cz_mPeOrydV9EyZ57Kc0_e_-4WAgSEA3cofPCvVjB7M_pd8uHPmRArDkcec7MU38wLZFymO.jpg)