Product guide

Manrose MixFlo MF100S 100mm Three-Speed Inline Duct Fan

Three-Speed: The Manrose MixFlo MF100S is a 100mm inline mixed-flow fan with three selectable speeds for ducted bathroom extraction. Its listed airflow varies by setting, while the claimed 24dB(A) high-speed noise figure is specified at 3m.

At a glance

Three speeds let the installer select the airflow and claimed noise level using an internal dip switch.
The manufacturer states a maximum airflow of 245 m³/h on high, with 216 m³/h on medium and 180 m³/h on low.
The listing specifies 100mm duct connections for rigid or flexible ducting and up to 200 Pa pressure for longer duct runs.
The fan is described as remotely switched, for example from a light switch, and its assembly can be removed from rigid ducting installations.

Price

£54.99Save 10%

Reference price: ~~£61.20~~

Price checked: 12 Nov 2026

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Pros and cons

Pros

Three selectable airflow settings allow operation to be matched to the installation.
Flexible or rigid duct compatibility and the stated pressure capability suit ducted extraction layouts, including longer runs.
The product claims IPX4 protection, double insulation and a ball-bearing motor.

Technical specifications

26 specifications

Identity
Brand	Manrose
Model	MF100S

Airflow and sound
Airflow on high	245 m³/h
Airflow on medium	216 m³/h
Airflow on low	180 m³/h
Airflow capacity listed	68 Cubic Feet Per Minute
Maximum pressure	200 Pa
Noise on high at 3m	24dB(A)
Noise on medium	22dB(A)
Noise on low	20dB(A)

Power and operation
Power use	20 to 25W
Wattage listed	25 watts
Speed selection	Internal dip switch
Power connector type	2-Pin

Dimensions and installation
Duct spigots	100mm (4") spigots (102mm outside, 98mm internal diameter)
Dimensions in feature listing	Approx. 298 x 175 x 195mm (L x W x H)
Dimensions listed	19.8L x 17.5W x 19.8H centimetres
Weight listed	1.83 Kilograms
Ducting compatibility	Rigid or flexible ducting

Materials, protection and service
Material listed	Plastic
Ingress protection	IPX4
Motor type	Ball bearing
Motor life claim	30,000 hours or 3 years
Warranty claim	3 year warranty
Maximum operating temperature	40°C
Electrical construction	Double insulated

What to know before buying

Listing details to confirm

The listing is inconsistent about dimensions: a feature gives approximately 298 x 175 x 195mm, while the details field gives 19.8L x 17.5W x 19.8H centimetres. Confirm the required clearance and exact dimensions before installation. Airflow and noise figures are stated for different speed settings, and the 24dB(A) high-speed figure is specified at 3m. The product title says 245 m³/h, while the details field separately lists 68 Cubic Feet Per Minute. Manufacturer claims are not independent measurements.

What’s in the box

Included

MF100S

Who is it for?

A good fit for

Bathroom or shower-room duct extraction where a 100mm inline fan and selectable speeds suit the planned duct run.
Installations using rigid or flexible ducting where the stated airflow and pressure figures meet the design requirements.

Less suited to

Buyers who need confirmed external dimensions before selecting a tight installation space, since the listing gives conflicting measurements.

Customer reviews on Amazon

4.6 / 5 · 787 ratings

5 stars74%74%
4 stars17%17%
3 stars6%6%
2 stars1%1%
1 star2%2%

Customer feedback highlights quiet operation, perceived quality, straightforward fitting and bathroom steam removal. Those points may matter for domestic ducted extraction, where the listing offers three speeds and names noise figures by setting. Durability feedback is mixed, so the stated motor-life claim should not be treated as a guarantee of an individual unit's service life.

Positive themes

Customers are reported to appreciate the quiet operation, perceived build quality, installation and steam removal.

Mixed feedback

Durability feedback is mixed, with some customers expecting long service and others reporting shorter life.

Frequently asked questions

What duct size does the Manrose MixFlo MF100S use?

The feature listing specifies 100mm (4") spigots and says the fan is suitable for rigid or flexible ducting. It also lists 102mm outside and 98mm internal spigot diameters.

What airflow does the MF100S provide?

The listing claims 245 m³/h on high, 216 m³/h on medium and 180 m³/h on low. These are manufacturer figures, not independently verified measurements.

How are the three speeds selected?

The speed is selected using an internal dip switch, according to the listing. The fan is described as being switched remotely, for example from a light switch.

Are the listed dimensions consistent?

No. A feature gives approximately 298 x 175 x 195mm, while the details field lists 19.8L x 17.5W x 19.8H centimetres. Confirm the dimensions for the selected listing before planning the installation.