Number of height settings
The number of cutting height settings provided by the lawn mower. The more such settings (with the same adjustment range) — the more accurately you can choose the mowing height. Note that in some robots (see "Type") this number reaches 30 or more with a range of 30 to 60 mm; in other words, you can select the height to the nearest millimetre.
Mulching
Possibility of work of a lawn-mower in the mode of a mulching.
Mulching is the chopping and automatic spreading of mowed grass over the site. This is one of the most convenient and at the same time practical methods of vegetation disposal. So, it does not need to be collected, and the resulting coating (mulch) performs a number of useful functions: it fertilizes the soil, reduces its heating and evaporation of moisture in hot weather, and also keeps the top layer loose.
Note that some lawn mowers allow you to use a nozzle purchased separately for mulching. However, such models are not included in this category: mulching in our catalog is indicated only for models that support this function out of the box.
Noise level
The level of noise produced by the device during operation. Usually, a certain average indicator is indicated in the characteristics — in the standard mode of operation; however, the actual values usually do not differ much from the claimed ones.
The lower the noise level, the more convenient the unit to use and the less tired the operator. In the case of lawn mowers, this is especially true, since such equipment is quite noisy — even the quietest models (some robots) give out about 47 – 48 dB, which is comparable to talking at an average volume. Note that the decibel is a non-linear quantity, and it is easiest to evaluate the actual loudness using comparative tables. Here is the simplest table for the values found in modern lawn mowers:
— 60 – 65 dB — talking in raised tones at a distance of about 1 m;
70 dB — loud conversation of several people at the same distance;
75 dB — loud laughter at a distance of 1 m;
80 dB — motorcycle engine, medium power vacuum cleaner.
90 dB — loud screams, freight car at a distance of 7 – 10 m;
100 dB — a subway train or a loud car signal at a distance of 5 – 7 m, an industrial workshop;
110 dB — tractor engine at a distance of about 1 m.
In addition to subjective sensations, there are specific sanitary standards that limit the impact of strong noise. So, according to European standards, noise of 85 dB is allowed to be heard without protective equipment for 8 hours, 91 dB — 2 hours, 97...dB — half an hour, and 103 dB — only 7 minutes. So when choosing a unit, you should take into account the duration of work with it — with high noise, you may need protective headphones.
