What size should a mini fridge be?
By use: as a drinks or second fridge, 30 to 45 L is enough (Klarstein Audrey, Bomann KB 7346). For a single household as the main fridge, 80 L makes sense (Comfee). If you also want to freeze permanently, you need a fridge-freezer with a large freezer section (Exquisit, 24 L).
Which mini fridge is quietest, for the bedroom?
The quietest is the thermoelectric Klarstein Silent Cool at 27 dB: no compressor, no vibration, just a quiet fan. It only cools relative to room temperature, however. Among the compressor units, 39 dB (Comfee, Bomann, Audrey) is standard and tolerable for most rooms. Rule of thumb: bedroom → thermoelectric (quiet), cold drinks → compressor.
How much power does a mini fridge use?
Depending on size and efficiency class, 60 to 170 kWh per year, so at about 35 ct/kWh (the German electricity price) around €20 to €60. Since the appliance runs 24/7, the energy efficiency class is especially important: the most economical in the comparison is the Bomann KB 7346 (EEK D). Watch out with the thermoelectric Silent Cool: actually EEK G, and despite being "quiet" the highest consumption.
Thermoelectric or compressor: which is better?
A compressor fridge actively cools to a fixed temperature (cold even in high summer), but has audible cycling and vibration. A thermoelectric unit (Peltier) is nearly silent and vibration-free, but only cools a few degrees below room temperature and needs more power. For real cooling and efficiency: compressor. For absolute calm in the bedroom: thermoelectric.
Mini fridge with or without a freezer compartment?
With a freezer compartment you can make ice cubes and store frozen food. The size decides: a small ice/freezer compartment (4 to 12 L, Audrey/Bomann KB 7245/Comfee) is enough for ice cubes and a few items (defrost manually), a real freezer section (24 L, Exquisit) for a stock. Without a freezer compartment (Bomann KB 7346) you get more cooling space, lower consumption and no defrosting.