Drying class describes the overall drying efficiency that the machine provides. It is denoted by a Latin letter, where A is the best efficiency, and further in decreasing order (
drying class B is inferior to
class A, but exceeds
class C). Naturally, higher efficiency machines cost more (ceteris paribus).
The direction in which the door of the dryer opens.
Most users are right-handed, so from this point of view, the best option is
leftward opening — the free space for loading and unloading laundry is just under the right hand. However, specifically in dryers, the
rightward opening is noticeably more common. It is because such units usually complement washing machines and are most often installed side by side. And in most washers, the door opens just to the left (again, based on convenience for right-handed people). Therefore, it is most convenient to place the dryer on the right and equip it with a hatch that opens to the right — this will allow you to overload the laundry from washer to dryer with minimal effort and time. And vice versa, if the door in the washing machine opens to the right, then it is better to choose a dryer with a leftward opening and install it on the left.
Sometimes both machines are installed as a column — a dryer on top of a washing machine. In such cases, the hatches of both machines should open in one direction — this is more convenient both from the point of view of ergonomics and purely psychologically. Moreover, if the "column” adjoins the wall sideways, then the opening should also occur towards the wall; otherwise, the laundry will have to be loaded and unloaded through the space between the open hatch and the wall, which can be very inconvenient.
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Note that in some dryers both opening options are claimed. It usually means that the door has a reversible mount, and the direction of opening can be chosen at your discretion. However, this feature does not hurt to clarify before buying.