How to choose bathroom exhaust fans

Let's try to figure out how to choose the right one and buy an exhaust fan for the bathroom.

Axial or centrifugal?

Axial or centrifugal fans are usually used for bathrooms.

For bathrooms, axial or centrifugal fans

The axial fan is arranged very simply: inside the plastic housing there is an electric motor with an axis on which a propeller with blades is mounted. Rotating, the blades tighten the air and take it out into the ventilation duct of the bathroom. The advantages of such fans are their compact size, light weight and ease of installation. Performance level (air exchange rate) they usually do not exceed 365 m3/h. They are used for small and medium-sized rooms, provided that the length of the ventilation duct is less than 2-3 m. The disadvantage of axial fans is a sufficiently high noise level (30-50 dB).

Centrifugal fans in the housing have a rotating rotor (wheel) with spiral shaped blades. The air is sucked into the rotor and, due to centrifugal force, is directed into the exit opening of the snail (a special spiral casing, shaped like a snail). The air is transported not only along the axis, but also perpendicular, and the fan blades are made of aluminium or steel. Centrifugal fans are often more powerful (maximum capacity can reach 1500-2000 m3/h) and can be installed in rooms with an area of more than 15 m². Their noise level can sometimes be lower than that of axial models.

Selection criteria

To make the fan work efficiently, you need to pick it up in accordance with the volume of the room

In order for the fan to perform its functions effectively, it is necessary to choose the right level of its performance in accordance with the volume of the room and the number of people living in the house. To find out the volume of the bathroom, you need to multiply the area by the height. For example, you have a bathroom with an area of 5 m². m with a ceiling height of 2.7 m. The volume of the room will be 13.5 cubic metres

Next, the volume of the room is multiplied by the multiplicity of air exchange. For a bathroom used by up to three people, the multiplicity of air exchange is 6, if more than three – 8. For example, multiply 6 by 13.5 and get a capacity of 81 m3 / h.

An important selection criterion is the noise level. It is desirable that it does not exceed 25-30dB. With a figure above 35 dB, noise can cause discomfort, especially at night.

Do not forget about security. Any electrical appliance located in a humid environment must be protected from moisture. It is recommended to use splash-proof appliances for bathrooms. A good indicator is the IPx4 code.

It is worth paying attention to the features of the fan installation. Wall and ceiling ventilation pipes are connected using flexible ducts. Channel models are installed in the opening of the ventilation duct. In this case, it is important to measure the diameter of the ventilation duct in order to choose the appropriate size of the device — 100, 120, 150 mm.

Adaptations wisely

The motion sensor ensures that the fan is turned on when motion detection in the room

Having dealt with the most important selection criteria, you can proceed to various "smart bells and whistles" with which manufacturers supply their equipment.

The timer allows you to programme a certain time during which the fan will work after the person leaves the bathroom. Usually, devices with a timer are turned on together with the light or at the expense of a motion sensor.

The motion sensor is triggered when people appear in the bathroom, the device turns on and off after they leave after a certain time specified in the timer.

The hygrostat (humidity sensor) allows the fan to turn on automatically when the set humidity level is reached and, accordingly, turn off when the humidity level in the bathroom returns to normal.

The check valve prevents the air from the exhaust duct from returning back to the room when the fan is turned off. This device is necessary especially where there is a single ventilation duct for the entire apartment. The check valve will not allow unpleasant odours to penetrate from other rooms, kitchens, bathrooms into the bathroom, and vice versa.

The clock on the fan panel will help those for whom it is very important to know the time spent in the shower.

Conditions for the fan

In order for the fan to ventilate the room normally, it is necessary to create conditions for it.

First. The fan needs fresh air. To do this, there should be a gap between the floor and the door.

Second. The ventilation duct in the bathroom should not be clogged. Otherwise, the fan will just run idle, because the steam will have nowhere to go. To check whether the vent channel is clogged, simply: bring a lighted match to it. If the flame fluctuates, then everything is fine. If it remains stationary, call a chimney sweep.

When can I do without an exhaust fan

If the draft of natural ventilation is sufficient, steam does not accumulate, odours do not bother, forced ventilation is not necessary at all. If the hood does not perform its function, before buying a fan, it is worth checking whether it is clogged. Perhaps, after cleaning, normal ventilation will be adjusted, and there will be no need for a fan.