Various kinds of exhaust fans are used to provide forced-air extraction from the room. They are used when it is necessary to get rid of excessive moisture, unpleasant odors, or simply create the desired microclimate. Exhaust fans are installed directly into the duct and are effective for use in a bathroom, toilet, or kitchen.
Varieties and features of exhaust fans for hoods
Different device models can differ significantly from each other in a number of characteristics. For example, there may be differences in the shape of the case:
- Round – mounted in round ventilation ducts, they are the most common option for use in the kitchen or bathroom.
- Rectangular exhaust fans – installed in ventilation shafts with a rectangular or square cross-section. As a rule, industrial fans are rectangular in shape, which is characterized by increased operating power.
- Square – just like rectangular exhaust axial fans, they are designed for installation in a square duct shaft and are distinguished by high operating power. They are also often used for industrial purposes.
Duct devices for air extraction are distinguished by design features:
- Axial – have a cylinder-shaped body, inside which there is a fan with blades mounted on the axis of the electric motor. With this design, air masses move along the axis of the device, and a special collector is often installed at the inlet, which improves the aerodynamic characteristics of the device. Among the advantages of axial fans for extraction, rather high efficiency can be distinguished – over 100 m³ of air per hour. In addition, axial models are characterized by ease of installation, therefore they are often installed in the ventilation openings of bathrooms or kitchens. The disadvantages include low pressure characteristics and a high noise level – about 30-50 dB.
- Radial – have a spiral housing, inside which there is a blade wheel. When it rotates, air masses move in the radial direction, the air is compressed under the action of centrifugal force and leaves the body. The blades of the radial device can be directed backward or forward, in the first case, during operation, saving up to 20% of electricity, and the noise of the device is significantly reduced. The forward-curved blades increase the fan power. Radial models are compact in size, so they can be easily installed in almost any air duct.
- Centrifugal is a relatively new model that has already gained great popularity among users. Exhaust centrifugal fans are well suited for installation in rooms larger than 15 m², high power, and virtually silent operation. The advantage of a centrifugal fan is that it can be installed not only in front of the air intake but also in the middle of the ventilation shaft.
Helpful advice! If you prefer a centrifugal fan, then it is better to install it directly in the ventilation shaft, so its efficiency will be much higher, and condensate will not accumulate on the device and dust will not settle.
There are also specialized models such as smoke exhaust fans and explosion-proof fans. Axial smoke exhaust fans are designed to move air masses in which a certain amount of impurities is present. This is a good option not only for production areas but also for kitchens where large quantities of food are often prepared. In addition, these models of hoods are very powerful and allow you to extract steam and smoke from the room in the shortest possible time.
The explosion-proof axial fan is designed primarily for the organization of forced air extraction with flammable or explosive impurities. Such models are rarely used in everyday life, but they are very popular in enterprises where there is an increased risk of fire or work with explosive substances.
How to choose an exhaust fan for the hood?
Before purchasing an exhaust device that will ensure the forced movement of air masses in the bathroom, toilet, or kitchen, you should pay attention to its following parameters.
Fan performance. This parameter is calculated using a fairly simple formula. To do this, you need to multiply the volume of the room by the rate of air exchange. The last indicator means the number of air changes per hour. The multiplicity directly depends on the type of room and is 6 for a bathroom, which is used by up to 3 people, 8 – more than three, and up to 10 – for a toilet.
At the same time, when choosing a silent fan for the hood, always take a product with slightly inflated rates. For example, the performance of an appliance installed in a bathroom should be 95-100 m³ / h.
The amount of noise generated by the instrument during operation. Any fan always emits mechanical and aerodynamic noise. The first is the noise from the operation of the electric motor, created by its vibration, which is transmitted to the air duct, the second is the noise from the movement of air masses. fans are models whose operating noise does not exceed 25 dB. An indicator exceeding the threshold of 35 dB is already noticeably annoying, so you should not install a device with such characteristics in a living room.
A fan can be made even quieter by installing a special muffler immediately behind the casing, as well as finishing the ventilation shaft with a material with high sound-insulating characteristics.
Construction safety. This refers to the level of protection against moisture and dust. This is especially true if you are purchasing an exhaust fan for a rectangular duct into a bathroom or kitchen, where high humidity is inevitably formed. If moisture gets inside the case, it can cause a short circuit, so it is better to immediately purchase models with protection against water. In addition, the purchase of a device operating at a low voltage of 24 V.
The functionality of the hood. This refers to the fan operating mode – automatic or standard. Standard axial supply fans turn on at the same time as the room light is turned on and are well suited for rooms where the humidity level is not too high. Otherwise, the device simply will not cope with air extraction. The automatic hood is equipped with a timer that switches the appliance on and off.
In addition, the design of the automatic fan can include a humidity sensor, which is very convenient for the bathroom. The price of an axial exhaust fan will be higher than the standard one, however, such improvements will allow you to more efficiently and quickly get rid of excess moisture in the room.
The quality of the device. If you need a really high-quality exhaust fan, then you should pay attention to that it meets international standards. For example, the minimum acceptable protection class for the device is IP 34.
When choosing a hood device, give preference to models that have already established themselves on the market and are popular among buyers.
Also, when buying an exhaust fan for the kitchen, pay attention to the fact that it can withstand high temperatures and high humidity. This is especially true if you are installing the device in the immediate vicinity of the stove. The cooker hood can be controlled using a remote control, a special cord, and it is also possible to turn it on simultaneously with the lighting. The most convenient way is to choose the remote option. You can also purchase a model with a built-in presence sensor, which will be triggered when you enter the room.
Instead of a ducted supply and exhaust, axial fan for the kitchen, a type of hood such as a window hood can also be used. A household window exhaust fan differs from other models in that it is built into the window structure or even embedded directly into the glass. The disadvantage of this option is to draft in the room if a check valve is not provided in its design. Today, window fans are not very popular, yielding positions to more convenient duct models.
Installation of exhaust fan
Before proceeding with the installation of the device, it is imperative to check the performance of the ventilation system in the room. To do this, you need to bring a lighted match or attach a sheet of paper to the ventilation hole. In the first case, the flame should deflect towards the hood, and in the second, the sheet should be held on the hole by the air flow. If this does not happen, then you definitely need an exhaust fan, since the air will not be removed from the room naturally.
After that, you should decide on the place where the axial fan for exhaust ventilation or another model will be installed. It is best to mount the device under the ceiling, as hot and humid air always rises upward.
Helpful advice! The choice of the type of fan is also based on the place of installation. Not every model is suitable for installation, for example, in a horizontal position or at an angle.
When installing the device, the following points should be taken into account:
- it is best to start installing the fan during the repair process;
- the wiring that goes from the power source to the hood should be hidden in a special box or even carried out under plaster;
- if we are talking about a fan in the toilet, then it is most convenient to connect it directly to a light switch;
- if you want to reduce the level of vibrations, as well as protect the supply and exhaust fan from external influences, then the device can be mounted in a plastic pipe previously fixed in the ventilation hole using cement, foam, or construction sealant;
- in the toilet, the fan will be most efficient if it is installed under the ceiling directly above the toilet;
- for error-free connection of the device to the mains, you should first familiarize yourself with the instructions attached to it.
The connection of an axial supply and exhaust fan is very simple:
- The protective cover is removed from the device’s body.
- A special adhesive mixture is applied to the fan.
- The device is installed in the place prepared for it, pressed tightly for several minutes.
- The protective cover is screwed into place.
Remember that the device must adhere as tightly as possible to the walls of the air duct, otherwise, during operation, it will beat against them, which will lead not only to an increased noise level but also to premature failure of the device and the need for repair or replacement.
It is also very important to choose a model that will fit the size of the ventilation duct as much as possible. For example, if it is 10 cm, then you need a 100 mm exhaust fan model.
Exhaust fans: care features
In order for the hood to serve as long as possible, certain operating rules should be observed and the device should be regularly inspected and cleaned. Most often it is necessary to clean the ventilation grill and fan blades of dust and dirt. In addition, when installing a fan of 125 mm or another model, it is necessary to check the duct for tightness of the joints. It is in the crevices that dirt most often accumulates, fatty deposits form, and bacteria, fungus, and mold multiply.
Duct blockages can be removed mechanically or chemically. In the first case, special brushes or simply pieces of fabric are used, in the second – cleaning agents. In especially severe cases, it is recommended to remove the fan, completely disassemble it, thoroughly cleaning all parts. Also, for more efficient and reliable operation, you should regularly change the filters, if such a possibility is provided by the design. It does not matter whether it is a VO 06 300 axial fan or another model, systematic cleaning is necessary in any case.
Helpful advice! In order for you to have to carry out major cleaning of the device less often, install a fine mesh on the inlet of the air duct. This will keep the fan blades from getting dust and dirt particles.
The organization of the forced movement of air masses from the room is very important if there is high humidity in the room or there are unpleasant odors. It is highly recommended to install an exhaust fan in the bathroom, toilet, and kitchen. The type of device is selected based on a number of characteristics discussed above.