Comparison Dreame D9 Max vs Dreame F9

The suction force provided by the vacuum cleaner. It is indicated by the maximum vacuum (negative pressure) that the unit can create at the working nozzle.

Note that this parameter is sometimes confused with the suction power described above, which is indicated in watts. Yes, suction force to some extent determines the efficiency of the unit. However, this efficiency also depends on the performance (airflow). And the suction power, indicated in watts, takes into account both of these parameters — it is determined by multiplying the suction force by the performance (see above for more details). For this reason, there is no strict relationship between this force and suction power: for example, a vacuum of 25,000 Pa can be found in models with 250 W, 200 W and even 150 W of power.

As for the practical significance of this spec, in general, a higher suction force allows you to work more efficiently with high resistance. For example, when processing carpets with a long pile. On the other hand, more pascals (with the same number of watts) means less airflow and, accordingly, less efficiency for large amounts of work at low resistance (for example, cleaning large rooms with parquet floors). Thus, it makes sense to pay attention to this indicator mainly in cases where high suction force is fundamental for you. In other cases, it is worth evaluating the capabilities of the vacuum cleaner in terms of suction power in watts.

Note that for a number of...reasons, the suction power is most often specified for robot vacuum cleaners (see “Produc type”). For such models, a value of 1500 Pa and below is considered very small, 1500 – 2000 Pa — medium, 2000 – 2500 Pa — high, more than 2500 Pa — very high.

It is also worth mentioning that the indication of suction force is often used as a publicity trick — to improve the impression of the product. For example, the suction power of 150 watts in itself is quite modest. But at the same time, the suction force of such a vacuum cleaner can be 25,000 Pa — a very impressive figure, especially for an inexperienced buyer, but having a very indirect relation to real efficiency. Especially often, such tricks are used among upright models and the already mentioned robots — these varieties initially do not differ in high power in watts. For many of these units, the characteristics only indicate the vacuum in pascals without specifying the suction power. It further enhances the impression: for example, in the specs of a modest robot, the figure "3000 Pa" looks much more impressive than "40 W". However, such figures have a very weak relation to the real capabilities of the unit and if they are not supplemented by data on suction power in watts, they should be considered solely as bait for a not particularly sophisticated buyer.

The nominal volume of the dust collector installed in the vacuum cleaner.

This indicator largely depends on the type of unit (see above). For example, in most handheld household models, the capacity does not exceed 0.5 L. The volume of the container in upright vacuum cleaners and robots can be somewhat larger — among the first variety there are quite a few models for 1 – 2 liters or even more, and among the second — by 0.6 – 1 liter and a little more. For conventional vacuum cleaners, the minimum figure is actually about 0.8 – 1 L; dust collectors for 1 – 2 L and 2 – 4 L are very popular in such devices; the maximum capacity is actually 4 – 6 liters — units of a similar layout, but with a larger capacity, are usually referred to as household ones. In turn, relatively small containers are occasionally found among workshop models. However, in vacuum cleaners of this type, the capacity is generally quite large — it can reach 26 – 50 liters or even more ; the same applies to industrial (construction) units.

In general, a larger dust container allows you to work longer without interruptions. On the other hand, a capacious container itself takes up more space and, accordingly, affects the size, weight and price. So when choosing th...is parameter, it is worth considering the actual features of the use of a vacuum cleaner. Here we can give such an example: for a full-scale cleaning of an average city apartment, a capacity of about 1 – 1.5 litres is required. Thus, say, a 4-litre bag allows you to carry out two such cleanings with sufficient efficiency without unloading the vacuum cleaner. There are more detailed recommendations regarding the optimal volume of the dust collector, including specific cleaning options. These recommendations can be found in special sources.

A capacity of a tank for water or detergent a vacuum cleaner with a wet cleaning function is equipped with. (see "Cleaning type").

Large capacity allows you to work longer without refilling the tank. On the other hand, an increase in capacity has a corresponding effect on the size, weight and cost of the unit. Thus, manufacturers choose this parameter taking into account the general specialization and the “weight category” of a particular model. So, in robots (see "Type"), the volume of the water tank is, by definition, small. Even in the heaviest models, it does not exceed 650 mL. But other types of vacuum cleaners can differ markedly in this parameter.

In general, for non-robot units, a capacity of 1 liter or less is considered very limited, 1 – 2 liters is small, 2 – 3 liters is average, more than 3 liters is above average. However, it much depends on the type. For example, in conventional vacuum cleaners, the capacity does not exceed 2.5 liters, and "for workshop" models this is very little — in most cases, they have a tank capacity of 3 liters or more.

Additional modes of operation provided by the robot cleaner (see "Product type").

First of all, let us clarify that the standard modes, in this case, include two formats of cleaning at standard power — continuous, in which the vacuum cleaner carefully cleans the entire room (or its specified area), and chaotic, in which it moves randomly within the working area. Other ways of working are considered additional; their list is given in this paragraph. Among the most common additional modes are spot cleaning (Spot), perimeter cleaning (Edge), and turbo mode. In addition, a fairly popular function is the Zigzag. Here is a detailed description of the different options:

— Spot cleaning (Spot). A mode that allows you to use the vacuum cleaner for targeted cleaning of a relatively small area of the room — for example, when spilling a small amount of debris. Most often, this programme works as follows: the robot moves to the centre of a user-defined zone, and then starts moving from this point in an expanding spiral and stops at a given distance from the starting position.

— Perimeter cleaning (Edge). A mode that allows you to start the vacuum cleaner around the perimeter of a given zone. By the name, it is mainly used for cleaning along the walls of the room: a lot of dirt accumulates in these places, which are difficul...t to remove when using standard cleaning modes.

— Turbo mode. Power mode for more suction force. Usually, the movement of the vacuum cleaner, in this case, can be carried out according to any programme available in the settings — both standard (combing, random movement) and additional (Spot, Edge, Zigzag). Anyway, the turbo mode is useful primarily for cleaning carpets and other floor coverings with pile, for which the standard power of the vacuum cleaner is not enough. However, working at increased traction increases the load on the unit and increases its wear. Therefore, most models have restrictions on the maximum time of continuous operation in turbo mode and sometimes on the minimum duration of breaks between switching on this mode.

— Zigzag. Zigzag movement is a kind of transitional variant between the orderly combing of the room and the random choice of direction. Zigzag allows you to achieve greater efficiency than chaotic movements. In addition, with such a movement, it is easier to compensate for the presence of various obstacles and ensure thorough cleaning of the entire given area.

The mapping system is provided in many modern robots. It allows you to determine the size of the room and the location of various obstacles present in it, as well as fix the route travelled by the vacuum cleaner. There are various systems according to their principle of operation, among which there are three types. Methods for building a map based on data from a sensor or a camera belonging to the basic level. But building a map using a laser rangefinder (lidar) gives more accurate results and elevates the device to a higher category. Accordingly, the presence of such a system affects the overall cost but provides several advantages. Firstly, cleaning efficiency is noticeably increased: the robot remembers which areas have already been cleaned and pays maximum attention to untreated areas. Secondly, movements are carried out along optimal trajectories, the shortest paths; this saves energy and extends battery life. Thirdly, it becomes possible to effectively clean large spaces of complex shape (for example, the entire apartment). And if the vacuum cleaner is controlled through an application on a smartphone or other gadget, the created map is displayed in this application. It gives various additional features: correcting the collected data, real-time device control, building routes, limiting cleaning through the application (see above), etc. P.

As for the methods of building maps (and further naviga...tion), there are mainly such options:

— Camera. Such systems work because the robot, using a digital camera, “examines” the room, remembering its shape and the location of objects. A fairly simple, inexpensive and at the same time practical way: usually, the camera is supplemented by an object recognition algorithm, thanks to which it can recognize obstacles stored in memory, regardless of their position in space. It is useful when you have items that are frequently moved around, such as chairs. In addition, if the map is displayed in an application on a smartphone, it looks like not just a conventional diagram but a real image, which is very convenient. The disadvantages of this option include perhaps a slightly lower accuracy than that of sensors and even more so rangefinders. However, it is not critical, and in some models, information from the camera can be supplemented with data from sensors, which completely reduces this drawback to zero.

— Sensors. Creating a map through the operation of various special sensors. Most often, such systems use sensors for obstacles and fall protection (see "Robot features"), working in conjunction with an inertial module that determines the current position of the robot in space. Receiving a signal from one of the sensors, the robot saves data on the trigger point; from such points, as a result, the map is formed. It is a fairly reliable method. It is inferior in accuracy to rangefinding cartography (see below) but it is also cheaper. The disadvantages of this type of mapping include some inconvenience when managing via the application. The map is displayed in the form of a scheme map, which is not always convenient for the user. In addition, vacuum cleaners with such systems are unable to respond in advance to a change in the situation — this change is determined only when the sensor is triggered again.

— Rangefinder (laser). Building a map using a laser range finder — lidar. Usually, such a rangefinder covers the space all 360 ° around the vacuum cleaner, scanning the space at a high frequency (hundreds and even thousands of measurements per second in all directions). It allows you to create very accurate maps in a short time and with a minimum of movement in space. In addition, the rangefinder is used not only during the initial mapping but also during further work. Thanks to this, the robot instantly reacts to changes in the environment and corrects the trajectory of movement. The main disadvantage of such systems is their rather high cost. In addition, as in the case of sensors, when controlling the vacuum cleaner from a smartphone, the map is displayed in the form of a scheme map, which is somewhat less convenient than when using cameras.

— Rangefinder + camera. It is the most advanced and functional option: the laser provides high accuracy in determining distances and a quick response to changes in the environment. And the camera allows you to create not just scheme maps but realistic images of premises that are convenient when controlled via a smartphone. The main disadvantage of such combined systems is their very high cost. Therefore, they are extremely rare, mainly in premium robot vacuum cleaners.

Types of voice assistants supported by the robot vacuum cleaner.

As the name implies, this function allows you to control the robot using voice commands. However, we emphasize that in this case, we are not talking about the voice recognition system built into the vacuum cleaner but about compatibility with an external device on which the corresponding voice assistant is installed — a smartphone, tablet, smart speaker, etc. Thus, to use voice control, an additional device will inevitably be required; on the other hand, there are no problems with the search for such a device nowadays. And in itself, such a control method often turns out to be more convenient than a command from the remote control or searching for the desired option in the control application.

As for specific assistants, the most popular nowadays are (in alphabetical order) Amazon Alexa, Apple Siri, Google Assistant. And in robot vacuum cleaners, compatibility can be provided both with one of them and with several at once. The specific control functionality available through the voice assistant should be specified separately for each model. It is also worth paying attention to the supported languages: for Siri, the language must be selected in the settings, for the Google Assistant, automatic language recognition is available (some adjustment may be required), and in Alexa (as of early 2021) support for the Russian language is not provided at all.

Cleaning area for which the robot vacuum cleaner is designed.

It is the maximum size of the room that the device can effectively process without the need to empty the dust container or charge the battery. It is worth choosing according to this parameter with a certain margin — this will give an additional guarantee in case of various emergencies. On the other hand, you should not take too much stock: after all, a large cleaning area requires more capacious batteries and capacious dust collectors, which significantly affects the dimensions, weight, and most importantly, the price of the vacuum cleaner.

As for specific figures, the most modest models nowadays are designed for 45 – 60 m2 — this corresponds to an average apartment with 1 – 2 rooms. And in the most advanced and heavy devices of this type, the cleaning area can be 300 m2 or even more.

The highest height of thresholds and various small obstacles that the robot cleaner can effectively overcome.

Most modern robots are able to effectively cope with obstacles with a height of 10 to 18 mm — this allows at least without problems to cross the edges of carpets, and small height differences at the boundaries of rooms (due to the difference in the type of coating), etc. But the models where the indicator is 20 mm or more are already referred to as robots capable of crossing high thresholds. However, even in such devices, the permissible height of obstacles does not exceed 30 mm. It is due to the fact that to overcome high obstacles, in particular, large wheels and high ground clearance are needed — and these features, in turn, increase the overall height of the robot, make it difficult to move under furniture and other low-lying objects, as well as reduce suction efficiency. On the other hand, even thin robots, whose height does not exceed 70 mm, can have very good crossing ability — for some of them, the maximum threshold height is about 25 mm.

The rated voltage of the battery used in the vacuum cleaner with the corresponding type of power supply (see above).

Initially, manufacturers select the characteristics of the battery (including voltage) in such a way that the vacuum cleaner can be guaranteed to deliver the power claimed in the specifications. Therefore, when choosing this indicator often does not play a decisive role. However, it can also be useful in such cases — for the most reliable comparison between models with different battery capacities in ampere-hours. See "Battery capacity" for details.

In addition, voltage data can be useful during operation — for example, to find a spare/replacement battery or a third-party charger.