Comparison Siemens LI 48632 stainless steel vs Bosch DHI 655 F stainless steel

The maximum flow of air or motor flow of air indicates the theoretical capability of the device. This parameter of the hood (motor) is measured during idle operation. By connecting the duct and working in the appropriate mode of extraction, the flow of air will be lower. However, high-performance motors will also give a high flow of air in extraction mode.

The level of noise produced by the hood in the loudest mode of operation. Usually (but not necessarily) it is the maximum power mode. It affects the comfort during operation of the device, so quiet hoods will be more preferable, but also more expensive.

The decibels in which the noise level is measured are non-linear units, so it is easiest to use comparison tables to estimate a specific value. Here is the simplest table for the values relevant in this case:

— 35 dB. The volume of a conversation in an undertone (but not a whisper). The lowest maximum noise value in modern hoods. Devices with such characteristics are almost guaranteed not to cause inconvenience: such noise is often blocked by other sounds, for example, the background noise of the street in an open window.
— 40 dB. The volume of a normal conversation. The maximum noise level allowed in a residential area during the day. If the hood is bought for home use, and it is supposed to be turned on often and for a long time, the noise level in the selected device shouldn't exceed this indicator.
— 50 dB. Conversation volume at medium tones.
— 60 dB. Raised conversation.
— 70 dB. Sound background on a busy street, in a crowd of people talking loudly, the sound of a vacuum cleaner motor at a distance of 2 – 3 m.
— 75 dB. Scream or loud laughter at a distance of about a metre.
— 78 – 79 dB. Loud mechanical alarm clock, motorcycl...e or truck engine. The highest level in modern consumer-grade hoods.

Note that the actual comfort of using the device depends not only on the volume but also on the timbre (tonality) of the noise: for example, a low, even rumble is generally perceived easier than high frequencies with clanging notes. If the hood installation is unsuccessful, the actual noise level may be higher than stated in the specifications. For example, additional noise can be caused by the hum of air in the ducts or rattling from the contact of the vibrating body with the wall. However, when choosing, it is worth focusing on the noise level claimed in the specifications.

The number of speeds at which the hood can operate.

The more speeds, the more accurately you can adjust the device's operating mode to a specific situation. At the same time, the vast majority of modern hoods have only three speeds which are enough for most occasions.

The number of motors provided in the hood.

For most modern models, one engine is enough — this is enough even for fairly high performance. Models with two motors are somewhat less common — usually, these are powerful performant hoods. One of the advantages of this design is that only one motor can be used at low speeds, and the second one can be connected only when maximum power is required. It has a positive effect on the minimum noise level (see above); on the other hand, the maximum noise level can be quite high, and such devices are usually more expensive than single-motor ones.

It is technically possible to use more than two motors. However, such models are single exceptions.

The control method provided in the hood.

— Push-buttons. The most popular control method in modern hoods can be provided in devices of any functionality and price category — from low-cost models, where buttons directly control the motor, to high-end solutions with advanced electronic circuits.

— Rotary knobs. Control with rotary knobs, sometimes supplemented by buttons or touch sensors. A rather specific option found mainly in high-end hoods, where rotary knobs are part of the design.

— Slider. Control using the lever moved on the special panel. Usually, only power is regulated in this way: the farther the slider is from the neutral position, the more air the hood draws. A fairly universal control method, found in hoods of all price categories.

— Touch controls. Control using touch panels is considered a sign of expensive high-end hoods. It is because it makes sense to use such panels mainly with advanced control electronics and they are poorly suited for low-cost devices. From a practical point of view, the touch controls are remarkable for their ease of use and ease of cleaning: a light touch is enough to give a command, and the panel itself has no slots or protrusions, making it easy to clean dirt.

The height of the entire hood structure is from the lower edge to the upper part of the body (the point of connection of the external air duct). For hoods with an adjustable design that allows you to change the height of the case, the maximum height is the size of the device in the unfolded state; in the case of non-adjustable hoods, this means a correspondingly constant overall height. When choosing a hood in height, it is worth proceeding from two points:

1. The optimal height of the air intake above the hob is 60-80 cm. This height allows the hood to capture kitchen fumes effectively and, at the same time, gives enough space to work with the hob.

2. Between the hood body and the ceiling, a clearance is required for connecting an external air duct.