Ducts for cooker hoods

The aroma of freshly prepared food in the kitchen is fine, but not very good, when the smell dissipates throughout the corners of the apartment and they are saturated with things. In order to avoid the spread of odors and steam during cooking, as well as the deposition of fat and soot on the walls and furniture, you need install a cooker hood. This device allows you to maintain a healthy atmosphere in the room and is absolutely necessary if you often cook at home. In order for the hood to perform its functions efficiently, it must be supplemented with an air duct. Ducts designed for kitchen hoods can vary in shape, diameter, material, so the choice of this element must be approached no less responsibly than the purchase of the hood itself.

Why is it better to choose a hood with an air duct?

This question may arise for everyone who chooses a hood in the kitchen. The fact is that there are devices that do not need to install an air duct, since they have a different principle of operation. Such

hoods are called filtering or circulating and purify the air from impurities with carbon filters. Unfortunately, this type of device is not efficient enough, expensive to operate, because it requires frequent filter changes, and is not represented in stores in a large assortment.

Retracting or evacuation hoods have greater performance and more successfully cope with air purification in the kitchen. The principle of their work is to draw in contaminated air from the room and remove it through the air duct to the ventilation system of the house. The capacity of such an exhaust hood depends not only on the power, but also on the parameters of the duct, which can vary significantly.

Types of ducts

Ducts for the evacuation hood can vary in several ways:

• in shape, configuration and diameter;
• according to the material from which they are made.

In its shape, the cross section of the duct can be:

1. round;
2. oval;
3. rectangular.

The choice of duct shape depends on the parameters of your kitchen. Round and oval channels take up more space than rectangular channels, so for small kitchens with a low ceiling, it is better to prefer the latter option. The flat rectangular channel for the outflow of air during installation can be hidden by laying in the strobes or masked using special designs. However, it should be noted that its performance is lower than that of round and oval counterparts.
In the manufacture of ducts, one of several types of materials is used:

• plastic (polyethylene, PVC and fiberglass);
• aluminum;
• steel.

Each of these materials has its own advantages and disadvantages.

Plastic ducts

Usually plastic ducts have a rectangular or circular cross section. Rectangular flat pipes look more aesthetically pleasing, round pipes are easier to install, since they do not require adapters to connect to the exhaust pipes and ventilation grilles.

Advantages

1. smooth inner surface, preventing the accumulation of dirt and fatty deposits;
2. corrosion resistance;
3. light weight;
4. ease of installation and connection of parts;
5. good sound insulation - during the operation of the hood, air noise is almost inaudible;
6. affordable price.

disadvantages

1. the need for additional acquisition of adapters and connectors;
2. low resistance to elevated temperatures.

Steel ducts

Can be made of galvanized or stainless steel. Stainless steel ducts are practically not used at home. Galvanized pipes are used for cooker hoods, but today they are no longer popular with ordinary people.

Advantages of galvanized ducts

1. smooth surface that does not impede the passage of air flow;
2. high temperature resistance;
3. low price.

disadvantages

1. greater weight in comparison with analogues from other materials;
2. the need to use sealing compounds to seal the channel;
3. when mounting a system of complex configuration, it may be necessary to cut metal;
4. high noise level.

Aluminum ducts

Advantages

1. versatility and ease of installation;
2. due to the flexibility of the pipe, installation does not require rotary fittings;
3. corrugated material can be stretched to a large length;
4. high temperature stability;
5. the cost is lower than that of analogues.

disadvantages

1. corrugated surface prevents the free movement of air flow;
2. fat and other deposits can accumulate in the grooves of the corrugations;
3. unpresentable appearance requiring camouflage;
4. instability to deformations and external influences.

Duct performance

Regardless of the type of duct chosen, several important points must be considered when planning and installing the system.

• One of the most important parameters to consider when choosing a duct is its diameter. To select the desired diameter, you need to measure the hole in the hood. The diameter of the pipe for the outflow of air should coincide with it or be slightly larger.
• The total length of the exhaust system should not exceed 3 meters, otherwise its effectiveness will decrease.
• The number of bends of the system should be minimal, with each turn the efficiency of the hood drops by 10%. If the number of knees is more than three, it is better to choose a flexible channel.

• Installation of a contaminated air exhaust system requires special measures to restore natural ventilation, as the air passage closes. The best solution would be to install a special valve on the ventilation outlet, the so-called “cracker”. During the operation of the hood, the flap closes one of the two openings - this ensures a forced draft. When the appliance is turned off, the shutter closes the second hole, which allows for natural ventilation.

• When using corrugated material, stretch it as much as possible in order to improve the flow through by reducing the grooves of the corrugation.
• It must be remembered that the system may need to be cleaned over time, so this should be foreseen during installation and made it collapsible.