Silent bathroom fan with check valve: selection and installation

Is it necessary to create forced ventilation in the bathroom or can you do with natural ventilation?

The designs of most private and multi-storey residential buildings provided only for a natural exhaust air circulation system in bathrooms. This led to the fact that during a shower, steam or an unpleasant odor was removed at a certain speed through a small ventilation hole.

External view of the ventilation grill covering the air duct of the natural ventilation system

Such a system did not always cope with the circulation of the required air volumes and dampness accumulated in the bathroom, creating an ideal microclimate for the development of bacteria or mold growth. The reasons for this were mainly errors in the design of ventilation ducts or their clogging during operation. In the worst case, the unpleasant odor could go in the opposite direction due to a change in draft, for example, when opening the door to the room.

Air flow visualization

When installing forced ventilation, due to the correct selection of hood performance, all these disadvantages can be avoided. As a pleasant bonus, it will be possible not only to remove polluted air, but also to take fresh air from the ventilation, if an appropriate ventilation system is used, or to provide mixed operating modes for blowing and blowing. That is, if you install an exhaust fan for the bathroom, you will have the following advantages compared to the natural method of ventilation:

• Increased air exchange with the same size of ventilation ducts.
• Complete absence of condensation on the walls or ceiling due to the high efficiency of steam removal.
• Improved room dryness.
• Stabilization of the temperature in the bathroom by exchanging air with the interior or exterior space.
• No accumulation of dirt in the channels due to powerful air currents.

Hood design with check valve

Types of check valves

An air vent valve is usually a mechanical device . It is made of galvanized steel , less often of stainless steel. There are plastic models. combinations on the market : a plastic case with a metal damper.

The material of manufacture must match the material of the hood or duct.

By opening method

Devices are classified according to the method of opening. There are 3 varieties.

• Manual valve - the valve must be opened and closed manually using a lever. It's not very convenient. In addition, the damper cannot completely block the opening to trap odors.
• Mechanical is the most popular solution. A mechanical or gravity valve opens and closes independently under the influence of air pressure.
• With an electric drive - the damper opens and closes forcibly, in accordance with the operation of the fan. Mounted only on systems with forced circulation.

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A manual valve, despite the obvious inconvenience, is necessary when the exhaust pipe is not led into the ventilation duct, but directly onto the street and the system is equipped with a fan. In this case, a manual damper, which opens only while the hood is operating, is more convenient: it does not freeze or get stuck, as often happens with a mechanical check valve.

By design

Check flapper valve
The sensitivity of the valve to air flow is determined by the shape of the damper and the method of opening. For it to work in natural ventilation, the membrane or petals that break the passage must be quite sensitive. In an inlet with forced ventilation, the damper may be simpler. But even in this case, it is necessary that the valve opens at the weakest fan operating mode.

Based on the shape and design of the device, the following varieties are distinguished.

• Rotary valve - clapper. A disk or rectangular fragment is fixed on a vertical or horizontal axis. Usually the axis is installed in the center of the hole, but it can be offset. The large damper area provides high windage, and therefore decent sensitivity. As the pressure increases, the valve rotates entirely. Disadvantage: When closed, the damper makes a loud bang, which is how it got its name. This noise is especially annoying at night. Silicone and rubber gaskets do not reduce noise. If the valve is installed on a system with natural circulation, the damper axis must be vertical. In this position, minimal force is required to open.
• “Butterfly” is a two-part damper. There are 2 half-disks installed on the vertical axis. They are held in the closed position by springs. The springs are weak and open even with a strong bang. However, if the draft in natural ventilation is weak, the valve may not work. The shape of the product is round.
• Membrane - the damper consists of 6 segments mounted on axes. The petals are made of thin flexible plastic. Under air pressure, they unfold separately or all together and open the ventilation hole. The diaphragm valve looks very mobile and sensitive, but it remains so only while it is clean. The accumulation of soot and dirt quickly weighs down the petals, they stick and do not turn.
• With gravity grille – reminiscent of flat blinds. The damper consists of several thin slats placed vertically or horizontally. The lamellas open or close under air pressure. Not the most sensitive option, but silent, so it is often mounted complete with a hood or placed on a ventilation grille in the wall.

The conventional design can be improved. For example, a heated model works effectively in cases where cold air rushes in from the street.

Criterias of choice

A ventilation grille with a check valve or a device in a hood must meet a number of criteria.

• Sensitivity - the damper should respond to weak blows of air. The more sensitive it is, the better.
• Operating temperature – some devices cannot operate under high heat and are therefore not suitable for the bathroom.
• specifications must match those of the fan. The latter opens the damper even in the weakest mode.
• Shape and dimensions correspond to the dimensions of the ventilation hole or pipe if the valve is mounted inside the duct.

Before buying a valve, you should make sure that the valve closes the hole as tightly as possible. The larger the gap, the less the structure is able to block odors.

Why is a check valve needed in a fan design?

When organizing forced ventilation, situations may arise when several fans operate simultaneously, taking in or releasing air. With complex trajectories of its movement, turbulences or pressure differences can be created. As a result, circulation may be disrupted and an unpleasant odor, along with the steam, will go into neighboring rooms. To prevent such situations, a check valve is used, which promptly closes access to the ventilated channel.

The principle of operation of the hood with an open check valve is shown.

Types of check valves for fans

Check valves may differ in material, shape, actuation mechanism, installation method, and throughput. Typically the material used is plastic or metal. Plastic is the most advantageous, as it is resistant to moisture, undemanding in maintenance and does not significantly increase the cost of the entire device. The metal has increased strength and is therefore resistant to various mechanical influences. A moisture-resistant check valve installed on a bathroom exhaust fan is identified by the presence of a protective coating.

Appearance of plastic check valve

Helpful advice! Plastic parts of the body and structure provide the greatest possible reduction in noise and vibration, unlike metal ones. Therefore, it is recommended to choose the first option for your home.

Metal check valve

The shape of the valve should follow the contours of the ventilation opening to ensure maximum hood performance. The standard shapes are: round, square and rectangular.

Methods of controlling the ventilation valve can be manual or automated. The former have increased reliability and low maintenance requirements. The presence of electricity or its absence will not affect their operation in any way. However, it is not always possible to close access to the ventilated channel in a timely manner, which can lead to negative consequences. The automatic design will ensure optimal operation of the system without external intervention and is therefore most suitable for use in the bathroom.

Related article:

Plastic air ducts and fittings for ventilation. A separate review provides useful information on the use and types of fittings for plastic ventilation.

How to choose the right silent bathroom fan with a check valve?

An exhaust fan for a bathroom should first of all be selected according to the type of design, since it is they that provide the main performance characteristics and efficiency. They are axial and centrifugal. Axial ones are a design in which the propeller is located in a plane perpendicular to the ventilation duct. They are usually made of plastic and are easy to install.

Axial design

Attention! It is recommended to install axial fans if there is not only a special mounting location for them, but also a horizontal section of the air duct at least 3 m in length. This is due to the fact that for such structures it is important to ensure minimal aerodynamic resistance.

Centrifugal ones are more powerful designs that can be installed even in clogged systems or in the presence of long air ducts. They can also be used if the ventilation system is single-pipe. Structurally, they consist of two parts: a housing and a snail-shaped turbine.

Centrifugal design

What additional fan functions should I pay extra attention to when choosing?

The silent bathroom fan with a check valve is distinguished by the possible presence of additional options:

• Constant ventilation mode. It differs from conventional standard ventilation in that the propeller is constantly turned on, but does not operate at a certain speed, but is capable of changing depending on the readings of the humidity sensor in order to dry the room. That is, at the same time, an energy-saving mode and an ideal microclimate in the bathroom are provided.
• Sleep timer. Allows you to leave the hood on without worrying about having to turn it off after a certain time.
• The hydrostat helps maintain an optimal level of humidity in the room using automatic control. This function is especially in demand in bathrooms that are frequently used or where there is increased dampness.
• The motion sensor will automatically turn on the device when a person enters the room. That is, it will effectively remove possible unpleasant odors. The shutdown is carried out automatically after a certain specified time.
• Splash protection will protect electronic parts from short circuits. The recommended minimum level of protection should be no worse than IP5.

Helpful information! It is recommended to purchase a suitable bathroom exhaust fan only after the required functionality has been determined. If it is missing an important function, it will have to be replaced, since there are no designs available today that can be configured to meet increased requirements.

Review of some fan manufacturers

The most well-known manufacturers of silent ventilation units include the following:

• Soler&Palau is a Spanish manufacturer that is a recognized leader in the production of high-quality and silent ventilation systems. It has existed for more than half a century and during this period it has not only increased production volumes, but also updated its main product lines. The production of components for ventilation systems has been launched in more than 10 countries. The turnover is constantly increasing and innovative changes are being made to the technical equipment of products. That is, this company is a brand name, and its products are guaranteed to have the stated technical characteristics.

Products Soler&Palau

• Maico is the standard of German ventilation technology. The company was founded more than 80 years ago in Germany, whose goal was to introduce innovative developments into equipment of impeccable quality and ease of use. Today, it consistently occupies a leading position and differs from competitors by the presence of a unique production line, as well as positive feedback from experts. The product range includes more than 1,600 items, and this indicates high professionalism and a desire for results, and not an increase in the number of products of mediocre quality.

Maico brand model

• Elicent is the official subsidiary of Maico in Italy . However, the main emphasis is on the functionality of the manufactured ventilation systems. Therefore, the cost of the product is lower than that of Maico, which is an excellent alternative for those people who do not require much luxury in the bathroom. Reliability and practicality at an affordable price allowed Elicent to compete with giant manufacturers in the ventilation equipment industry and, it is worth noting, very successfully.

Elicent device

• The domestic company Vents has been on the ventilation equipment market relatively recently, only 26 years, but over these years it has been able to compete with foreign brands. The research and production base allows us to create high-quality products that are fully adapted to domestic operating conditions. All products are certified and meet international quality standards. At the same time, the cost of fans is much lower than their analogues.

Products Vents

• Hoods from the Italian company Vortice are distinguished by increased reliability, safety and a completely aesthetic external design, which differs significantly from competitors. The company's priority is the principle of an integrated approach and the introduction of large-scale scientific achievements in its products. The model ranges are diverse with very specific differences.

Vortice brand fan

Fan prices by manufacturer

Fan prices largely depend on manufacturers and product functionality. Therefore, it is necessary to choose a compromise option that will satisfy all the main selection criteria. Average prices in Russia are shown in Table 1.

Table 1. Average prices for fans in Russia

Making the final choice of a fan for the bathroom hood

The main selection criterion is to ensure sufficient hood performance, that is, power. This parameter is key influenced by the area of ​​the bathroom and the volume of air that stagnates in it. Therefore, you first need to measure the height, length and width of the room. The volume is calculated by multiplying all the listed quantities. Then, in accordance with current standards, you need to multiply the resulting value by the air exchange rate. For a bathroom, this coefficient ranges from 3 to 8.

Helpful information! It is recommended to take the average value of the multiplicity factor and round the resulting power value to the nearest whole number.

Another, no less important indicator is the level of electrical safety. In a humid environment with the possible presence of water vapor, it is recommended to choose designs in which the power connection can be made outside the bath or all conductive and contact parts are reliably protected. For safety reasons, you should give preference to low-voltage devices that are powered by direct current of 12 or 24 V.

How to choose a fan

When selecting a silent bathroom fan with a built-in check valve, you need to take into account a number of criteria:

• performance;
• noise level;
• execution;
• additional options;
• manufacturer's reputation.

Types of silent devices
To determine performance, you need to know the volume of the bathroom and the number of residents. The volume is determined simply. You need to multiply the height, length and width of the room. The frequency of air exchange depends on the number of residents. For example, for a family of three, the average coefficient is 6. To calculate productivity, the volume of the room is multiplied by the correction factor.

Fan performance is selected with a margin of at least 15%.

You need to keep in mind that a completely silent fan does not exist. A person feels comfortable at a noise level of less than 35 decibels. If the noise level value in the device passport is less than 35, you don’t have to worry.

According to their design, fans can be ducted or overhead. Ducts are installed in the air duct itself. At the same time, it must be mounted as deeply as possible to reduce the noise level. Most often, such devices are installed in large rooms. The most compact is the channel device. But it is not able to completely dampen vibration. The overhead creates much less noise.

For standard small rooms, overhead fans are more often used. They are mounted either on the ceiling or near a vent on the wall. In addition, the devices must be reliably protected from moisture and splashes. The protection class must be at least IP 34.

External view of a fan with a check valve

In addition, the exhaust fan must be equipped with elements to save energy. This function can be performed by a control panel, motion sensor or timer. There are also fans equipped with a humidity sensor. Such devices turn on when the air humidity reaches a given value. The main thing is that the device works only when it is really necessary. The reputation of the manufacturer is also important. The service life of the device depends on this.

Installation of a fan with a check valve

It is recommended to install a silent bathroom fan in the air duct itself or externally, built into the wall or ceiling in a special exhaust airlock. Step-by-step installation is performed in the following sequence:

• We connect to the power supply depending on the availability of means for monitoring the operation of the device and the characteristics of the electrical wiring.

Electrical connection diagram

Attention! Before installation work, it is necessary to de-energize the entire apartment, or locally only the bathroom. When connecting inside the bathroom, it is recommended to ensure an adequate level of electrical protection. If there are doubts about the quality of the laid wiring, it is recommended to replace it or lay a new one along the surface of the wall.

Prepared hole in the wall for installing a hood

• Carefully remove the decorative trim from the front side of the case.

Removing the decorative panel

• On the reverse side, at the point of contact of the device body with the exhaust pipe, along the junction line, apply a thin, uniform layer of glue or silicone grease. This will allow you to obtain a reliable and sealed contact.

Applying glue to the line of contact with the duct

• We place the body of the device in its place of fastening and press it firmly against the wall. If excess glue has formed, then immediately remove it from the decorative finish with a dry, thick cloth.

Inserting the housing into the seat

• If there are fastening points for screws or bolts, then be sure to screw them in so that in case of possible vibrations the structure is held securely.
• We install a mosquito net.
• We fix the front panel.

Installation work completed