Home »  What to Look for When Choosing 4 inch inline duct fan?

 What to Look for When Choosing 4 inch inline duct fan?

2022-02-03 hqt
4 inch inline duct fan

The smells of fried onions from the neighbors, puddles under the windows and on the walls, fungus and mold in the bathroom, aromas from the restroom hovering around the apartment ... It looks like you have problems with ventilation. We've broken down the top 4 inch inline duct fan so you can choose the best one for your space's needs.

Types of duct fans

The modern market is filled with models of duct fans for every taste and budget. The principle of work is divided into:

  • mechanical;
  • with timer;
  • humidity sensor;
  • with motion sensor.

Mechanical - the most simple

4 inch inline duct fan comes with an external (connection to a light switch) or built-in switch. This type of fan is the most economical. But not practical! Turning on with the light, the fan may not have time to draw out moisture and air while you are in the bathroom or restroom.

Fans equipped with a timer, as well as mechanical ones, are connected to the switch. But they continue to work for the programmed time (from 2 to 30 minutes) after turning off the light.

The humidity sensor is usually an optional feature for fans with a delayed shutdown timer. When the humidity level is above normal, the fan automatically turns on until it does its job.

The motion sensor activates the fan only when there is someone in the room, significantly saving energy costs.

What to Look for When Choosing 4 inch inline duct fan?

4 inch inline duct fan 2022

Before choosing a duct fan, you need to check the “viability” of your ventilation ducts in your multi-storey building. Make it easy. Open a window for ventilation, and attach a sheet of thin paper (toilet paper, paper handkerchief) to the duct opening.

If it holds, then the ventilation duct is working and you can start choosing a 4 inch inline duct fan. If not, then you need to contact the utility services to solve the problem, since the problem of lack of air ventilation cannot be solved even by buying the strongest fan.

When choosing, the future owner needs to know such parameters as:

  • connection diameter;
  • the area of ​​​​the room for ventilation;
  • frequency of use;
  • wall color / interior style.

The first step in choosing 4 inch inline duct fan is measuring the diameter of the ventilation duct. The most popular models come with a connection diameter of 100 mm and 150 mm. But in the modern market you can find models of any non-standard connection sizes - from 110 to 400 mm.

The next step in choosing a fan is to determine the required power

 It is necessary to proceed, first of all, from the area of ​​\u200b\u200bthe room. For bathrooms up to 9 sq.m., the capacity should not be less than 90 m3/h. If the bathroom is combined with a restroom - add another 30-40 m3 / hour, total - at least 120 m3 / hour. If the bathroom area is more than 9 sq.m - look at the fans with a capacity of 150 m3 / h and more.

Be aware that fans make noise. And if it is too strong, it will certainly interfere with the residents, especially at night. Therefore, pay attention to the noise level that the fan you choose produces. 

Up to 25 dB - you will hardly notice its operation, from 25 to 32 dB - barely audible noise, from 32 to 40 dB - audible during switching on and during operation, over 40 dB - a rather noisy fan, but is allowed for use in residential premises from 7:00 am to 11:00 pm.

4 inch inline duct fan Take Less Space

And of course, not the last place is occupied by the style of the interior and the fan in it. To make the device inconspicuous, to put an accent or to complement the interior is not a difficult task now. 

4 inch inline duct fan manufacturers bring to the market all new models in a different color palette, with decor and lighting. Decide what color you need and choose the best of the models presented in the top.

Best 4 inch inline duct fan Fans 20222

As mentioned above, the modern choice of fans pleases. Though red, even green, square or round, quiet or very quiet, with a humidity sensor or with a timer ... But, most importantly, as with the purchase of any household appliances, it is necessary that the device be of high quality. 

Let's look at all the pros and cons of the 10 most popular models of household duct fans among BT-Service buyers.


These fans have become popular for a reason. Engaged exclusively in the production of ventilation equipment, the Hgductfan knows all the subtleties and requirements of users. Therefore, it works so precisely and skillfully with the closure of such urgent needs as low noise, high performance and design.

Users note the soundlessness of its work and at the same time high performance. 4 inch inline duct fan is suitable for all standard ventilation ducts. Turns on and off in tandem with a light switch.

A distinctive feature of this model is that in addition to classic white, it is available in black, bright red, metallic, gray and other colors. The manufacturer managed to achieve such a low noise level by equipping a small 7.5 kW ball-bearing motor with rubber inserts to absorb vibrations.

 An additional bonus is that the motor is protected from overheating and, like other electronic components, is hidden behind a hermetic cover. This makes the fan suitable for use in rooms with high humidity.


  • Low noise level.
  • Productivity is 97 m3/hour.
  • Durable to moisture and ultraviolet plastic housing and impellers.
  • A non-return valve that prevents air from the ventilation duct from entering the room.
  • Economical.


  • Design

HI-100IS 4 inch inline duct fan

A small and very neat-looking 4 inch inline duct fan, imperceptibly for residents, copes with the tasks - constant or periodic ventilation of amenity premises. The high level of moisture protection - IP34 makes it suitable for use in rooms with a high level of humidity. It is installed both on the wall and in the ceiling. The front panel comes with decorative overlays for even greater fusion with the interior of the room. .


  • Stylish appearance.
  • Possibility to add aluminum decor.
  • Burnout-resistant plastic housing and impellers.


  • An additional check valve is required.
  • It does not always have time to draw out air during the time the user is in the room.
  • There is no timer.