How to calculate the required performance of the hood for the kitchen. How to choose the hood power for the kitchen

The atmosphere of the house is more or less protected from the dusty and gassed street, but defenseless from the air pollutants produced by the kitchen. Agree that there are very few open windows when cooking.

An exhaust hood is needed above the stove and a ventilation duct with an outlet "to the street", but first - the calculation of the hood for the kitchen to select equipment with a suitable power. But how to do it, so as not to involve specialists?

We will try to tell you - in this material the procedure for performing the calculation is considered in detail, formulas and specific examples of calculations are given. Also selected visual photos and useful video advice on the selection and installation of hoods.

In modern apartments above the stove is placed, better known as a hood. Many homeowners are convinced that this airbox is responsible for ventilating the kitchen.

Therefore, with a clear conscience, they lead the ventilation duct pipe from the hood into the vent designed and built by the designers of the high-rise building.

What happens if the regular ventilation in the kitchen is blocked by an air duct from the exhaust hood? The intensity of air exchange in the apartment will drop sharply.

Hood installers and kitchen umbrella vendors usually claim otherwise. They will say: this technique will significantly improve the quality of the air supply at home, because it has a powerful ventilation unit.

However, the power of the cooker hood has nothing to do with ventilation. The reason is that the air exchange in the apartments of most residential high-rise buildings, especially those built before 2000, was designed with the expectation of.

The principle of air exchange in a multi-storey building is based on supply air sources (windows, vents, etc.) and exhaust ducts (fig. on the left). The latter are vertically displayed through all floors of the building. The kitchen hood can be connected to the channel (fig. right) or not connected

Outdoor air entered through the cracks of the window frames and the front door. And the channels in the bathroom and the bathroom were used to remove "stale" air. It would seem - what is it?

Extractor hood in the kitchen - to extract air. So why can’t you “stick” an air duct from an exhaust hood into it? It's all about air performance.

Features of the kitchen hood

For models of exhaust hoods, the power is much higher - 200-1100 m 3 / h. This power is needed to draw into the air duct the volatile pollutants formed during cooking.

However, hood sellers state another reason for choosing the power of the hood - the need for frequent air exchange in the kitchen.

The exhaust box installed above the stove is not responsible for the air exchange in the kitchen. This device only removes volatile products of cooking. Symbols: A - removal of combustion products from the stove, B and C - direction of air movement in the process of air exchange

The standards for mechanical ventilation really state 10-12 multiple changes of air in the volume of the serviced premises ( SNiP 41-01-2003).

But the hood located above the stove does not perform the function of "ventilation of the room", because it is not capable.

The air in need of renewal (replacement) accumulates near the ceiling. The exhaust hood is not capable of sucking it into the ventilation duct - its socket is not set high enough. And the air flow during ejection and injection behaves differently.

An electromechanical installation draws air from a distance not exceeding the diameter of the suction socket. Those. with a hood width of 400 mm, air will be drawn into it, located no further than 400 mm from the socket.

Meanwhile, the release of the air flow occurs at a distance exceeding 15 diameters of the exhaust opening.

A simple "home" example: a household fan turned on. From its reverse side, the movement of air is barely noticeable, but from the front - a powerful air flow. By the way, the vacuum cleaner works to suck dust only at a minimum distance from the carpet.

The only effective way to remove volatile food products is an independent ventilation duct. Otherwise, the smells will remain in the house.

The exhaust hood above the stove performs the only task - to remove the air that has come to it from the surface of the stove.

Of course, instead of the pumped air, another portion of it will come to the stove from the window, the open door to the next room, etc. But a complete change in the air volume in the kitchen will not happen.

If the smells of cooking food rise to the ceiling, they will not participate in the mixing and are difficult to remove.

For this reason, the instructions for exhaust hoods contain the following conditions and work: 600 mm from the electric stove; 750 mm from the gas stove; air currents (drafts) should not be allowed during operation of the hood, otherwise odors will spread throughout the room.

The cooker hood does not provide air change in the kitchen. When choosing its model, the air volume of the room does not matter. The relationship between the size of the kitchen and the power of the exhaust hood was invented by the sellers of kitchen appliances.

When making calculations for the selection of a kitchen hood, the following factors should be taken into account:

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You also need to make sure that the ventilation unit is in good condition and that there is power supply to it.

The operation of the hood can also be prevented by drafts that prevent the vertical movement of convection air flow from the stove. If the problem of a “weak” hood is not detected, its source is outside the kitchen.

The performance of the exhaust hood depends on the section of the ventilation duct, where the fumes from the stove go. And homeowners often install an overly powerful hood, or assign it an exaggerated mode of operation.

Residential property owners follow a simple logic - the stronger the fan pulls, the better the volatile contaminants are removed from the stove.

This is not true. The performance and performance of the kitchen hood system directly depend on the throughput characteristics of the ventilation duct.

The output of the ventilation channel for the kitchen hood on the facade of the building will ensure the safety of draft in the ventilation duct. It is mandatory to install a non-return valve and a lattice cover

For example, a ventilation duct for supply and exhaust air exchange, located in the wall of a house, is not able to remove more than 150 m 3 / h of air.

Firstly, the cross section of such ventilation ducts does not exceed 130-140 mm, which is not enough for mechanical ventilation. Secondly, regular duct ventilation in high-rise buildings is long and contains multiple irregularities.

The instructions for the ventilation unit usually contain a diagram showing the relationship between pressure in the ventilation duct and performance. An increase in pressure causes a decrease in the performance of the hood.

The ventilation ducts in the houses are assembled clumsily: uneven walls; solution streaks; narrowing due to offset blocks; many turns. Or even - the ventilation shaft may be clogged. In such a situation, without

Attempts to set increased performance to a ventilation hood connected to a house ventilation channel have the opposite effect.

The stronger the air flow, the more intensively it is prevented by defects in the section of the ventilation duct. And if the actively forced air cannot move forward, it moves backward.

A simple example is a soccer ball. The more air is pumped into such a ball, the more difficult it is to work with a pump. Pressure becomes an obstacle - there is a lot of air, it tends to go back through the tube, pushing the pump handle.

The situation is similar with an increased power hood - the more intensively the air is supplied, the more its work is blocked.

The ideal ventilation duct for a kitchen hood is short, with a minimum of bends. Therefore, it is required to remove air from the stove not through the supply and exhaust channel, but through a channel made specifically for the exhaust hood.

An opening in the facade wall, a rigid or flexible duct (ideally round), and a lattice air intake at the outlet of the duct. This is how a kitchen hood should be equipped.

It takes ~2 minutes to read

If you are tired of constantly ventilating the kitchen, and the issue of air purification remains unresolved, then it's time to purchase a powerful hood of the desired model. Before buying, you need to make sure that you have taken into account all the nuances - from functionality to decorative features. And for this you need to be well acquainted with the characteristic qualities of the most common models available for sale, as well as calculate their power.

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Among the huge range of kitchen hoods, you can choose models of any size and shape. Many buyers first of all choose a beautiful design or a well-known brand. But the appearance of these devices is much less important than their technical parameters - the power and volume of air pumped per unit of time.

An improperly selected hood for a given room will not be able to effectively clean the air in it. Its performance index, measured in m 3 / h, affects how much polluted air it can pass in an hour. With the help of special calculations according to a simplified formula, you can independently choose the most suitable exhaust technology for your kitchen. A more accurate calculation can only be made by a competent engineer.

What is the difference between exhaust and ventilation

The ventilation system is a network of channels built into the walls with access to the outside of the building for the exhaust air from the room. In this case, the influx of fresh air occurs through the door and window openings in a natural way.

This air exchange system according to sanitary standards should be installed in all residential premises. But it is not very efficient, and even more so is not able to localize and remove odors, fumes, soot and other "charms" of life. To prevent them, forced ventilation is installed - an exhaust hood. It collects all the vapors from the hob, directs them through the duct to the ventilation system.

Extraction device

According to the principle of operation, they are all similar to a vacuum cleaner, but with different functions. Modern exhaust devices come in different designs, depending on the purpose - some only remove polluted air, while others filter it and return it already cleaned. According to the cleaning method, they are divided into flow, recirculation and combined, which combine both options.

• Flow hoods equipped with metal or plastic pipes (round, square, corrugated) for connection to the ventilation system, which are rigid or flexible. The lower parts of the device consist of filters () that trap soot and grease. They are camouflaged behind decorative panels. Inside are fans and special motors. Behind them is an air duct connected to ventilation.
• Recirculation they work autonomously, without being connected to ventilation, therefore they do not have pipes, which makes them look more aesthetically pleasing. Inside their cases, after the fans, there are replaceable, very thin carbon filters. For coarse cleaning, the filters are made of durable aluminum, they can be simply washed with detergents. Outwardly, the principle of the structure of the cases is the same as that of flow-through ones.

The exhaust system is powered by electricity. Everything is very simple - it is plugged into the outlet, the button with the selected mode is pressed (indicated by the numbers 1-3), the engine is gaining momentum. The most convenient hoods for connecting are with touch displays or with remote control (using a remote control or voice commands).

Types of exhaust systems by shape and placement methods

According to the structural features of the body, there are several varieties:

• flat- the most compact, without additional installations. Suitable for small spaces. But they have a short service life, they need to be replaced periodically. Among the flat ones there is a kind of inclined, located at an angle to the hob and having a small size.
• Dome– powerful and functional, they clean large rooms well. They are quite large and have the shape of hemispheres or pyramids.
• Also available cylindrical(adjustable in height), square, conical, round and other non-standard forms.
• Embedded models differ from the previous ones by the possibility of their disguise in furniture, ceiling, niche in the wall.

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According to the placement features, there are hoods:

• suspended– mounted to the wall or ceiling in any area of ​​the kitchen;
• insular- fastened to the ceiling in the center of the room;
• corner- are installed at two adjacent walls for more rational use of space.

Requirements for exhaust devices and their installation in the kitchen

To ensure the efficient and safe operation of these devices, several installation rules must be observed:

• The dimensions of the intake hole must be larger than the area of ​​the hob.
• The distance from the surface of the stove to the hood should be at least 70-80 cm to avoid overheating.
• Its capacity should be such as to provide a complete replacement of air at least 10 times per hour.
• If the kitchen does not have access to a special ventilation shaft, then it is better not to connect it to the usual one so as not to disrupt its operation, or even better, install a recirculation model.

How to calculate the power and performance of a kitchen hood depending on the area of ​​\u200b\u200bthe room

The higher the power of the hood, the faster the air will be purified. The required performance for a given room can be found in the table, where the calculation is based on the area of ​​\u200b\u200bthe kitchen and its height. The cheapest models have the lowest productivity, approximately 200-300 m 3 / h. They can only be installed in small kitchens and subject to not very frequent cooking on the stove. If the hob is used frequently, then the power should be at least 600 m 3 / h.

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The formula for calculating the power of a kitchen hood

Calculations can be done using a simplified formula yourself:

Q- exhaust power (m 3 / h);

S- kitchen area;

H- the height of the kitchen;

12 - coefficient (number of air replacement cycles per hour)

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According to sanitary standards, 10-15 air replacement cycles should occur within an hour. Coefficient 12 is the selected average.

For example, S= 10 m2, H=2.5 m2

With these values, you get:

Q=10 × 2.5 × 12 = 300 m3/h.

Other factors to consider

Calculations according to the formula have an average value, because other nuances must also be taken into account:

• Type of hob. For an electric stove, the coefficient reading can be up to 15, because apart from the fumes from the products, no other substances enter the air. But with a gas stove, harmful substances from burning gas also enter the air. In this case, the coefficient is taken from 20.
• Extraction type. When flowing, it is necessary to take into account the throughput of the existing ventilation shaft. With recirculation, this factor does not matter.
• Room layout. If there is an open entrance to the next room or the door often opens there, then it is necessary to take into account the large area of ​​\u200b\u200bthe room when calculating.

Choice of kitchen hood

If funds allow you, choose a model that works in two modes - combined (). This is a more convenient option. There are already models on sale that work almost silently - with a level of no more than 40 dB. An alternative to one powerful engine is a system with two, but less powerful ones, which make much less noise. Fans play an important role in the operation of exhaust devices. Best of all withstand the maximum loads tangential and diametrical. The size of the hood should be larger than the area of ​​​​the hob so that steam and dirt do not fall on the ceiling.

Video: rules for calculating the required performance of the hood

Among the abundance of models presented for sale in stores, it is difficult to immediately navigate and make the right choice. The correct calculation of the power of the exhaust system, the choice of a model of a suitable size and method of operation will allow you to create a healthy microclimate and safe conditions in the house.

Musty stale air in the living room, fumes and rich smells of food in the kitchen, exhausts and amber of fuels and lubricants in the garage - such conditions suggest that how to calculate draw power.

Hood power calculator

Somewhat earlier, such a factor influencing the choice as the noise emitted by the exhaust system was mentioned. We should not forget about this property of turbines built into kitchen ventilation, because it directly depends on the power, that is, the number of revolutions per minute, as well as on the diameter of the channel and the number of elbows in it, the distance to the ventilation shaft, the density of filters and other trifles. Therefore, you always need to find a compromise between the desire to buy more powerful equipment and the desire to spend evenings in the kitchen in a cozy environment.

According to the facts, the comfortable noise threshold in the room is no more than 30 decibels (db), this is the so-called background noise - the distant roar of motors of cars passing along the street, birds chirping outside the window, the murmur of water in the pipes. At the lowest speed, a truly quiet hood emits no more than 35 dB, at the second speed - within 45, at the third - about 50 dB. When compared to household noise, this is equivalent to a whisper at 5 meters from you, a conversation at 10 meters and a quiet conversation at 3 meters, respectively. Accordingly, a noise threshold of 55 dB can be considered uncomfortable, given that there is always enough work in the kitchen.

If you do not pay attention to decibels, then the calculation of the hood is very simple. You have a certain volume of the room, the so-called cubic capacity, within these limits the air must be constantly updated, preferably at least 12 times per hour. So we first calculate the volume of the room, multiplying its length, width (this will give us the area) and height V=S. H, and then we multiply the result by the same 12 complete air purifications. However, this number of ventilations is usually calculated for the maximum load of the hood, that is, it will mean prohibitive noise in the kitchen during the same hour. Therefore, be sure to add at least 15% to the result of multiplications (ideally 30%) and get V. 12 . 15=P, that is, the power determined by cubic meters per hour (m 3 / h).

The choice of hood is largely influenced by the type of hob, due to the different amounts of combustion products emitted into the air. So, for an electric panel, they are completely absent, as well as for an induction panel, and for a gas one, along with soot. Therefore, for the first two in a 3x4 meter kitchen, a minimum capacity of 486 cubic meters per hour is sufficient, and for the third, at least 650 cubic meters of air for the same time. Accordingly, the coefficient of air renewal in the room for electric hobs is taken as 15, and for gas hobs 20 times per hour. It is logical that if the doorway is devoid of a closing sash and has turned into an arch, the power should be increased due to the spread of odors and combustion products, and for the same surfaces it will already be within 600 and 800 m 3 / h, respectively.

Unlike the kitchen, the room reserved for the car should be much better ventilated. And this is logical, since it is difficult to compare a gas stove and an internal combustion engine in terms of the amount of combustion products released. Therefore, before you calculate the hood, you need to decide which vehicles and in what quantity you will put there. The emissions of a car and a truck vary greatly in volume and content of harmful substances, especially if the former requires high-octane gasoline, and the latter quietly consumes diesel fuel. According to the air exchange standards established by ABOK, it is necessary to provide air flow in the amount of 180 cubic meters per hour for one passenger car.

It is not recommended to make many bends, because the more there are, the stronger the noise of the exhaust system. In addition, each knee reduces ventilation efficiency by approximately 10%. In order for the air drawn out by the turbine to be replenished at the same speed, several inlet openings can be made by supplying them with retraction fans. The entrance channels are located closer to the floor, at a distance of 40 centimeters from it, and are covered with a fine mesh to prevent the penetration of rodents.

Properly calculated power plays a significant role when buying a device. Specific odors during cooking and frying food, fumes, burning, smoke - all this is removed by this device. However, this is only possible when its performance meets the desired characteristics.

In order not to purchase just an elegant kitchen accessory instead of a working device, you need to calculate the power of the hood before going to the store. And for the correct calculation of the formula, you need to understand the design and principle of operation of the exhaust device. All the necessary information can be found in this article.

What is power calculation for?

The amount of exhaust air the hood can replace per hour will depend on the performance of the engine and it is measured in cubic meters. The main task of this device is the destruction of specific odors in the kitchen, as well as the timely removal of fat, soot, fumes, which are inevitably present during cooking and frying food.

How to calculate the hood in the kitchen so that the performance complies with the conditions of SNiP. Having picked up and installed an extract of the required power, the costs of it will be compensated over time by saving detergents.

Factors affecting power calculation

To calculate the performance of a kitchen hood, the formula is used:

Q=s × h × 12.

It takes into account only the size of the room, the height to the ceiling and the frequency of air exchange. This is a correct calculation, but not a complete one.

In addition to the area of ​​\u200b\u200bthe kitchen, the following parameters must be considered:

• family composition (consumption of clean air must comply with sanitary standards per person);
• cooking frequency;
• what dishes are prepared (with fatty broth or healthy food);
• section, length, material of air ducts.

And also the type of stove and the location of the room affect the power of the device. Let's take a closer look at the last two parameters.

Plate type

Undoubtedly, the area and type of plate has an impact on the performance of the hood. The type of stove affects the amount of waste in the form of scale, burning, getting into the air at the time of frying meat, boiling borscht, or healthy food with vegetables alone. At the same time, the flow of fresh air into the room also occurs in different ways. Consequently, the air exchange rate also changes.

Let's take a closer look at how this happens:

1. The calculation of the hood for the kitchen in the presence of an electric stove differs from the classical one, since combustion products do not penetrate into the air, except for steam from cooking food. As a rule, the air exchange rate for these electric stoves is increased from 12 to 15 when calculating, while the classic formula will also change as follows:

Q=S×H×15.

1. At the time when a gas stove is used, the air exchange rate increases to 20. This is due to the fact that, in addition to fumes, combustion products in the form of burning, soot, burnt, and so on enter the air space above the stove. Here the performance calculation formula will be different: S × H × 20.
2. It would be wrong to say unequivocally that with a hob with an area of ​​​​65 cm, the hood should be more productive than with a smaller stove of 55 cm. However, logically, this can be assumed, because large hoods process the air mass from the plate of a larger surface. It is simply impossible to completely remove all harmful particles and odors from cooking with low power.

It is important not to make mistakes when calculating the device parameters. It is much easier to calculate the power of the hood, if you take into account the main aspects.

Kitchen location

When calculating the performance of a kitchen hood, the type, area and isolation of it are taken into account. It can be: an apartment in the form of a studio, a kitchen and a living room at the same time, a separate kitchen. And also in the opening, instead of the door, an arch is sometimes installed, or the door is constantly open, in which case these parameters must be taken into account.

Here, the kitchen, one way or another, is combined with the neighboring room, so the conditions for calculating the performance of the hood increase several times. Thus, when calculating the power of the device, you need to take into account these additional parameters in the adjacent room, thereby fully providing your household with fresh air.

There is an opinion among users that in a small kitchen a hood with a small power is enough. But in a small room, odors disperse faster, which means more polluted air.

Accordingly, in order for the air to be clean, air exchange must occur more often. However, a hood with low power simply cannot provide this, or the engine will overheat and burn out sooner or later.

The greater the power of the kitchen hood, the sooner the air above the stove in the kitchen is cleaned. Performance can be quickly calculated from the table below.

Extractor performance

In small kitchens, it is allowed to install low-power exhaust devices with a capacity of 200-300 m³ / h. The price of these devices is relatively small and they perform their task under certain conditions: cooking occurs no more than two or three times a day and in small volumes. With more frequent “cooking”, it is better to use a classic hood with a capacity of 600 m³ / h.

On a note! The performance of the device is indicated in m³ / h. Sometimes it is called power. However, this value cannot be used as power consumption, which is specified in watts (W).

Performance must comply with SNiP standards. During an hour of operation, air is replaced approximately 10-12 times. For calculations, as a rule, they take the number 12. If households often smoke in the kitchen, then the performance of the unit increases by 20-30%.

Power calculation

As already known, to accelerate the calculation of the performance of the device, the following formula is used:

P=S×H×12, where

P– calculated power value;

S- the area of ​​the room;

H- ceiling height;

12 - replacement of the air mass in the kitchen according to SNiP.

This formulation is suitable for relatively small volumes of air in the room, up to 40 m³. With its help, the smallest power of the hood is determined. In practice, this value can change, as other aspects also influence it: the type of hob and air circulation, the composition of the family and the location of the kitchen.

For an illustrative example, let's calculate the performance of the hood for a kitchen measuring 12 m 2.

For this, the following initial data are given:

• room dimensions 12 m2 (3 × 4);
• distance to the ceiling - 2.8 m;
• family members - 3 people;
• the electric stove is used 3 times a day, for it the air exchange rate is 15 according to sanitary standards (coefficient 1.5);
• air duct available.

To calculate the performance of the hood, it is necessary to substitute the input numerical values ​​\u200b\u200binto the formula:

(3 x 4) x 2.8 x 12 x 1.5 = 604.8 m³/h

Therefore, the calculations showed that for a kitchen with dimensions of 12 m 2, the productivity of the apparatus is at least 600 m³ / h. That is, it moves a given mass of air in an hour. It will not be difficult to choose a product with these parameters in any price range.

What to look out for

When choosing a device, first of all, you need to find out if there is a possibility of connecting to exhaust ventilation. If the room has this bandwidth - very good. In the case when there is no possibility of connection, you will have to purchase a hood with special filters built into the device.

Hood type

Devices are divided according to the principle of operation, and more specifically, according to the method of removing the air flow from the hob.

There are two types of exhaust devices:

• flowing;
• recycling.

1. The first type of instrument designed to connect it to the ventilation duct and to exhaust the exhaust air to the outside. Moreover, such hoods are combined. They can bring the air flow outside, or they can immediately return it back, having previously passed it through the filters.

Such modes are selected at the will of the owner, basically, the second option is convenient to use in winter, so as not to cool the kitchen with cold air during replacement. Before connecting the hood, you need to check the draft in the channel, for this it is enough to bring the flame of a candle or match to the hole and make sure that it deviates towards the channel.

If the draft in the well is weak, then you must first clean it, otherwise the hood will not fully cope with its task. Another option is to bring a separate ventilation duct outside with further insulation.

1. Second view- recirculation is equipped with a filter system, and such devices do not need to be connected to a ventilation duct. In these hoods, the purification of the air mass takes place in two stages. First, particles of fat, burning, and scale are removed by mesh filter elements.

Then the air mass passes the second cleaning through activated carbon, after which all unpleasant odors disappear and then the air returns back to the kitchen. During operation of the unit, the filters resist air circulation, and this must also be taken into account when calculating the performance. It is recommended to increase the rate for such units by about 20-30%.

Noise level

When buying a hood for the kitchen, you need to pay attention to its noise level, since the sounds produced by various household appliances can cause your discomfort. How to find out the noise level from the installed device? This indicator is indicated in the instructions from the manufacturer. Modern hoods have a noise value of 30 to 70 dB.

An acceptable indicator according to SNiP is a level from 30 to 45 dB. In the case when the digital value of the hood is greater, then its work will be loud. The more massive the walls of the exhaust device, the quieter it will work, since all sounds will be absorbed inside the device.

Sometimes manufacturers make soundproofing outside the unit, using different sound-absorbing materials for this. And also, in some models, instead of one, two fans with less power are built-in, which significantly affects the overall noise level downwards.

As a result of these design changes, modern hoods have the lowest noise level.

1. Performance. The more powerful the device, the more effectively it will set the air in motion. Therefore, with such work, it will create more noise. Therefore, you should not purchase a hood with a power exceeding the calculated one for this room.
2. Number of operating modes. Choose a hood for the kitchen with several modes. In this way, noise can be reduced by setting the process to the minimum value. When choosing, you do not need to buy a model with a noise level of more than 45 dB.
3. Noise level value. Periodically clean the filters of the first stage and change the carbon filter elements of the second stage in a timely manner, since they also significantly increase the noise level in a dirty state.

Finally

It is not easy for an ordinary man in the street to navigate and make the right choice among the presented models of exhaust devices. At the same time, if the device is purchased with the appropriate power, the right size, then the operation of this unit will allow it to provide a pleasant atmosphere and a healthy microclimate in the apartment.

When choosing a ventilation device, people often pay attention only to the design of the unit or the brand. But they forget about the most important parameter - this is the power of the hood for the kitchen (performance). Without the correct selection of this parameter, even the most beautiful unit of a well-known company will not be able to cope with its task - to effectively purify the air in the room. The performance indicator determines how much polluted air the device can pass through itself in a certain time, it is measured in m 3 / h.

The higher the power of the unit, the faster the air in the kitchen will be cleaned. Performance can be quickly calculated from the table below.

At a minimum, industrial kitchen ventilation devices have a capacity ranging from 200 to 300 cubic meters per hour. The cost of such models is low, and they cope with their task with difficulty. You can install low-power devices only in small rooms, provided that you do not cook very often. For frequent cooking, it is recommended to use standard installation(capacity - about 600 cubic meters per hour), or with increased pumping volume - about 1000 m 3 / h. Accordingly, the price of such devices is higher.

Power calculation

To calculate the performance of the hood, you first need to understand what functions the device should perform. According to the instructions, this device should purify or remove polluted air in the kitchen. According to sanitary standards, 12 air replacement cycles must pass within one hour. That is, he must change indoors 12 times in 1 hour. Now you know where the coefficient “12” comes from in the formulas for calculating productivity.

The formula itself looks like this: Q=S*H*12, where:

• Q is the power of the unit, which is measured in m3 / h;
• S is the area of ​​the room for which ventilation is needed;
• H is the height of the room;
• 12 is a coefficient indicating indoor air replacement cycles.

For example:

• room area - 12 m 2;
• height - 2.7 m;

We substitute the values ​​into the formula: Q=12*2.7*12=388.8 m3. Based on this calculation, the device will produce such a volume, only using the maximum performance. It will not survive this mode for a long time and may fail.

This creates a small power reserve for a kitchen hood, facilitating the operation of the appliance. And for you, it is possible to turn on the maximum mode only during a large smoky room, for example, on the eve of the holidays, when a large number of dishes are being prepared.

It should be noted that all these calculations for the volume of air exchange have averaged indicators, since various nuances are not taken into account:

• type of hob;
• room layout.

hob type

The type of stove determines how much pollutants can be released into the air during cooking. And updating it, respectively, should occur more often or less often. The update factor must also be changed. The calculation of power for the kitchen differs from the standard one, since no combustion products enter the air, except for fumes from cooked food. The coefficient for such slabs can be increased from 12 to 15, and the formula will look like this: Q=S*H*15.

Extractor hood over electric stove

When you are going, the coefficient should be increased to 20. This is done so that in addition to fumes from cooked food, a large amount of harmful gas combustion products enter the atmosphere. In this case, the formula is written as: Q=S*H*20.

Hood over gas stove

Hood type

The units differ in the mode of operation, namely, where the passed air is discharged. There are 2 types of devices:

• ventilation;
• recycling.

Devices means connecting it to ventilation channel in the house, for the removal of exhaust gases to the outside. But before calculating the power, the bandwidth of the channel must be taken into account. If the house is old and the ventilation shaft is clogged, then even though you buy a powerful hood (according to the calculations), it will not be able to remove the air at full strength. And to the neighbors in the riser, exhaust gases from your kitchen will be blown into the room. In such cases, you can do separate exit for ventilation to the outside by making a hole in the wall.

Devices contains in design filter system and does not require connection to the ventilation shaft. In most cases, cleaning occurs in 2 stages. First, the first filter absorbs large particles: steam, grease and fumes. Then the air passes through a carbon filter, which removes all odors, and flows back into the room.

Filters can create some resistance during pumping, which also needs to be taken into account when calculating the performance of the hood. The recommended increase in this value for such devices is approximately 30 - 40%.

Room layout

When calculating the ventilation performance, the layout of the kitchen should be taken into account. If, for example, an arch is installed instead of a door, or you are used to not closing the door, then the volume of the adjacent room should also be taken into account in the calculations.

If kitchen combined with dining room or living room, then the requirements for calculating the performance of the device increase significantly, due to the rapid spread of odors that must be effectively removed.

Noise level

Now that you have calculated the required extractor power for your kitchen using the above recommendations, you should think about the noise that it will make. In a store, when choosing a device, you are unlikely to be able to assess the noise level of the device due to the large size of the room or other noises in the sales area. It will help to correctly evaluate this indicator instruction that comes with the unit.

The more powerful the device, the stronger the sound it makes.

In the instructions, you should look at the sound parameters at maximum load and in the normal mode of the device. If the noise level is in the range of 30 to 45 decibels in standard mode, then the operation of the device will not cause you discomfort. Such hoods can practically be called. When working at maximum, the sound should not exceed 55 decibels. If this indicator is exceeded, then such a device may be suitable only for large rooms. Otherwise, the loud sound will cause discomfort.

Following the above recommendations, you will be able to choose the right hood power for the kitchen. And this, in turn, will contribute to the creation of a pleasant indoor climate and well-being during cooking.