When choosing a suitable model of a cooker hood for the kitchen, attention is paid not only to its design or brand identity. We should not forget about such an important parameter for air purification as the power of kitchen hoods (or their performance). Without a correct assessment of this indicator, even a very attractive-looking unit from a well-known manufacturer is unlikely to be able to effectively clean the air in the house from the vapors accumulated in it. Its performance determines how much of the contaminated air masses can be pumped in a given period of time. Competent calculation of the hood necessarily precedes going to the store and buying it.
Types of hoods for the kitchen
A large assortment of ventilation products of various classes is presented on the domestic market. It takes into account the peculiarities of the kitchen area and the design of the hood itself. Among the samples presented on these grounds, the following performances are distinguished:
- dome model;
- hidden in furniture items;
- telescopic;
- flat.
- T-shaped (island) or box-shaped.
The first type of exhaust structure is mounted directly above the stove, forming something like an air-sucking dome. It is notable for its considerable dimensions and has an attractive appearance, reminiscent of an expensive fireplace. Concealed range hoods are practical models that can be built directly into kitchen furniture. Its owner can only see a small part of the product with the control panel removed outside.
The inner space of the cabinet in which such a device is mounted may be used for other purposes. This type of kitchen ventilation is represented by relatively inexpensive models suitable for users who want to save on space occupied by the equipment. Telescopic hoods are also discreetly mounted; to bring them into working position, it is enough to push out the panel with the grease filters mounted in it.
Flat structures operate in the mode of natural circulation of air masses through the air ducts connected to them and are among the simplest devices of this class. Installation of such systems, as a rule, does not cause difficulties, since they do not need to be connected to the existing ventilation system. They are suspended directly above the slab parallel to the wall.
Island or T-shaped appliances are intended for large kitchens or in the presence of ventilation systems combined with a bathroom. They are mounted on walls or ceilings directly above the worktop and have a fairly high power rating. This category also includes box models that look like a pipe or steel box and are good at eliminating odors in the kitchen and bathroom.
Design and principle of operation
When considering the device of exhaust structures, it is important to pay attention to the fact that they, in principle, differ from ventilation systems. The latter are niches arranged in the walls that allow exhaust air to be removed outside in a natural way.In this case, the inflow of fresh air masses is possible only through gaps in door and window openings. This method of air exchange is characterized by low efficiency and is not able to completely remove the odors present in the kitchen, as well as remove soot and other household vapors. For these purposes, you will need special devices that provide forced ventilation, called hoods. With their help, the vapors emanating from the hob or stove are collected in one place, and then through a special air duct they are removed through the ventilation ducts.
Principle of operation
In accordance with this factor, all devices offered on the market are divided into three types:
- recirculating (without diversion to the operating ventilation);
- flowing;
- combined.
Hoods without outlet to the ventilation duct contain special filters and a forced intake system by means of a built-in fan. During operation, they pass polluted air through a system of filter elements, and after cleaning it, return it back to the kitchen.
Flow models are connected directly to the air duct available in the kitchen. Fresh air enters through it, after which the contaminated layers are removed forcibly. Combined type devices are capable of alternately operating in one of the two modes discussed above.
Hood device of various modifications
Modern fume hoods are manufactured in several designs that determine their purpose. Depending on this, they are divided into hoods that only allow you to remove dirty air, as well as models that filter it and return it back to the system in an already purified form. Flow-through devices contain a set of soft plastic or rigid metal pipes of a certain shape. They are used to connect to the ventilation system.
In the lower part of such products there are special filters (grease traps) that trap soot and grease emanating from the stoves. From above they are masked with special decorative panels, and in the inner area there are fans and a drive motor. Behind these structural elements is an air duct connected directly to the ventilation.
Since the recirculation devices operate autonomously, they are devoid of outlet pipes and are more aesthetically pleasing in appearance. In their inner space, immediately behind the fans, there are replaceable thin filters. In terms of design, they differ little from their flow-through counterparts, with the exception that their operation requires a connection to the electrical network. The most convenient models of hoods in this regard are equipped with touch screens and have a remote control.
Regulatory requirements
Existing sanitary standards determine the requirements for kitchen hoods without being tied to specific models. In this case, it is assumed that they are not intended for organizing ventilation of the room, but serve exclusively to remove contaminated air from the stove. For them, the ceiling area is also inaccessible, which forces them to choose a model that can only serve the space above the hob, for example, or above a conventional gas stove.
The performance of the hoods is linked to sanitation requirements as follows:
- An indicator of effective work is the mode when the air in the kitchen is renewed at least 10 times in one hour.
- The average indicator for different rooms used in the calculations is selected from a range of 10-15 times.
- For typical kitchens, it is taken equal to 12 units.
If the owners constantly smoke in this place, the required capacity of the unit increases by 15-30 percent.
Recommended power
The power of cooker hoods or their performance is an indicator of how efficiently the unit cleans the air in the room. This parameter is expressed in cubic meters of air mass passed through them in a fixed time. When determining it, they proceed from the current sanitary standards and the requirements of SNiP.
With the correct selection of a model with the required power, the cost of purchasing it will fully pay off over time due to the abandonment of detergents and medications. When calculating this indicator, it is important not to be mistaken in either direction. It is recommended to calculate the power of the hood for the kitchen taking into account the factors that actively influence its value.
Exhaust power calculation
As the simplest way to calculate performance, use the formulaP = SхHх12, Where
- P - the required power indicator;
- S - kitchen area;
- H - ceiling height.
Number 12 corresponds to the standardized air renewal rate.
This formula is only applicable for rooms with a volume of up to 40 m³. With its help, it is very easy to calculate the minimum power of the exhaust equipment. However, the actual amount of intake air depends on many factors, including:
- type of pollution source;
- ventilation system design;
- the layout of the kitchen itself;
- place of installation of the hood;
- method of organizing the inflow of air masses.
At the same time, the exhaust device does not replace the missing ventilation system.
As an example, the hood power for a kitchen with an area of about 12 sq m will be calculated.In accordance with the formula, the required characteristics of the equipment are first determined. In this case, the following initial data is taken:
- Kitchen area - 12 sq. m (3x4 meters).
- The ceiling height is about 2.7 meters.
- The number of people living is 3 people.
In addition, the kitchen has a hob that comes on at least 3 times a day and has a separate air outlet.
To calculate the performance of a kitchen exhaust device, you will need to substitute the indicated numbers in the formula, after which you get:
P = (3x4) x2.7x12x1.5 = 583.2 m³ / hour.
1.5 is a coefficient taken for an electric stove and taking into account the design features of the equipment. It turns out that the optimum performance of the exhaust device for such a kitchen is at least 600 m³ / hour. It will not be difficult to find a model suitable for the calculated indicator on the market.
Noise level and other important characteristics
During their operation, any models of hoods produce extraneous sounds. If you hear a noise similar to rattling or vibration, this indicates that there is a play in some place - the case or air duct is not firmly fixed. When the fan blades are heavily soiled, the characteristic hum of the exhaust system will be heard.
Since when the hood is activated, the motor that rotates the fan blades is also running, this process is also accompanied by a clearly distinguishable hum. By the nature of the sounds emitted during the operation of the system, some users manage to understand with which node they are connected and whether the latter needs cleaning.
The most important characteristics of exhaust devices also include:
- dimensions of the unit used;
- its power;
- method of cleaning air masses;
- the presence of a built-in filter and fan.
Knowing all these parameters will allow the interested user to easily choose the model suitable for his kitchen.
Rules for choosing a hood for the kitchen
When choosing an exhaust device, first of all, its dimensions are taken into account, set by the dimensions of the kitchen stove or hob. If we take into account that their width is in the range of 45-90 cm, manufacturers offer models with a fixed range of parameters (50, 60, 90 and 120 cm). In addition, attention is paid to the installation height of the hood.According to the current regulations, it is supposed to be hung at a distance of 0.75 meters from the surface of the pollution source.
The performance of the purchased device must be sufficient to clean the polluted air, taking into account the number of people living in the house. You should also ask what filters are built into the selected model.
It makes sense to purchase recirculation units with charcoal filters for rooms where it is not possible to connect to existing ventilation.
